Ask Language Log: pronouncing apoptosis

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From AB, MD (CPT, MC, USA):

I have an odd inquiry that I'm hoping you'll oblige. My question is about the preferred pronunciation of apoptosis. I believe the scientist who originally described this phenomenon asked a linguist to invoke an image of an Autumn tree shedding a leaf. We are now in an intense debate about the most accurate pronunciation of this word. As a long time language log reader, I was hoping you could help us settle this fiery debate. How do you pronounce apoptosis? Thank you very much! 

I have no special expertise in this matter, since I know the word mainly from reading, and have probably not had the occasion to say it more than a couple of times in my life. But FWIW, I would have said (in IPA) something like


The OED more or less agrees, giving

/ˌapɒpˈtəʊsᵻs/ , U.S. /ˌæpəpˈtoʊsəs/

Wiktionary gives

(UK) /ˌapɒpˈtəʊsɪs/, (US) /ˌæ.pəˈtoʊ.sɪs/, /ˌæpəpˈtoʊsəs/

The deletion of the second /p/ in the first U.S. version presumably reflects the etymology  ἀπο– "away from" + πτῶσις "falling", where the idea is that the 'p' is silent in ptosis (in English), like in ptomaine or pterosaur.

(By the way,Wiktionary's audio rendition for the UK version

seems confusingly different from the UK IPA transcription.)

Merriam-Webster gives

\ˌa-pəp-ˈtō-səs, -pə-ˈtō-\

with the audio rendition

which suggests that by /a/ they mean /æ/.

Summing it all up, it looks to me like the standard U.S. pronunciation would probably be something like the OED's


The silent-p-in-ptosis idea strikes me as unwise, because likely to confuse people. And the OED cites Nature 1994 to the same point:

1994   Nature 28 Sept. 98/2   The ‘p’ in ptosis is silent, and on that basis students are commonly exhorted to pronounce apoptosis as apo'tosis… The silent ‘p’, however, appears neither correct nor attractive in words in which the Greek-derived ‘pt’ occurs in the middle of a composite word.

The argument, I guess, would be that the silent initial 'p' is due to the phonotactics of English, where initial /pt/ is not allowed. But in the middle of the word, resyllabification can occur, licensing the /p/. [Like the /p/ in helicopter or lepidoptera, or the /g/ in agnostic, etc., as commenters point out…]

Hope that helps.

But wait.

I was originally skeptical of the story that "the scientist who originally described this phenomenon asked a linguist to invoke an image of an Autumn tree shedding a leaf". According to the OED, the word was in use from the 18th century, if not earlier, in the (now rare or obsolete) sense "A resolution, relaxation, or loosening of something":

1749   J. Barrow Dict. Medicum Universale   Apoptosis, the same as Apolysis, which see. [Apolysis, a solution, or release, which is diversified according to the subject, as, the exclusion of the fœtus, of the secundines, or the solution of a disease.]

The modern meaning ("Death of individual cells, characterized by condensation and fragmentation of the nucleus and cytoplasm and usually followed by phagocytosis by other cells, typically occurring as a self-activated process involved in the regulation of cell numbers, as in normal development, and in the growth of tumours") is first cited from 1972:

1972   J. F. R. Kerr et al. in Brit. Jrnl. Cancer 26 239 (title)    Apoptosis: a basic biological phenomenon

But in 1972 the word would have been available in medical dictionaries. And in 1749 and before, any physician would know Greek, and wouldn't need a linguist to coin a term like apoptosis.

But I was wrong. The full 1972 reference is JFR Kerr, AH Wyllie and R Currie, "Apoptosis: A Basic Biological Phenomenon with Wideranging Implications in Tissue Kinetics", BJC 26: 239-257 (1972). And Kerr et al. thank a Greek scholar, Prof. James Cormack, and recommend that the second 'p' be silent!

Thus, although the development of this distinctive type of necrosis, which has previously been called shrinkage necrosis on morphological grounds (Kerr, 1965, 1971), can, in fact, be triggered by noxious agents (Kerr, 1971), it often appears spontaneously or in response to known physiological stimuli, and it is clear that its implications in tissue kinetics are of widely ranging importance. It is not confined to vertebrates (Goldsmith, 1966),  and we suspect that further work will confirm it as a general mechanism of controlled cell deletion, which is complementary to mitosis in the regulation of animal cell populations. Because of its important kinetic significance we suggest that it be called " Apoptosis ".*

* We are most grateful to Professor James Cormack of the Department of Greek, University of Aberdeen, for suggesting this term. The word " apoptosis " (ἀπόπτωσις) is used in Greek to describe the "dropping off " or "falling off " of petals from flowers, or leaves from trees. To show the derivation clearly, we propose that the stress should be on the penultimate syllable, the second half of the word being pronounced like " ptosis " (with the " p " silent), which comes from the same root " to fall and is already used to describe drooping of the upper eyelid.

I still tend to agree with Nature 1994 that the silent /p/ is a bad idea.

But the controversy is not going to be settled easily, it seems.

I should add that the Liddell & Scott entry for ἀπό-πτωσις doesn't mention anything about falling leaves or petals:


  1. ThomasH said,

    July 3, 2015 @ 5:58 am

    FWIW, I prefer a -POP-to-sis. A-pop-TO sis sounds like a disease, not a normal cellular process.

    [(myl) It's a free country, as they say. But in matters like this, norma loquendi can't freely be ignored. So unless you persuade a lot of other people to your point of view, your attempt to avoid the connotation of disease for that word will give others the impression that you're ignorant rather than eccentric.]

  2. Stan Carey said,

    July 3, 2015 @ 6:28 am

    For me it's /ˌæpɒpˈtoːsɪs/, though I probably have a schwa in the second syllable sometimes. I studied it briefly in microbiology at uni, and used to puzzle over the second-p-dropping variant I occasionally heard. Oxford Dictionaries gives /ˌapə(p)ˈtəʊsɪs/.

  3. L Gittlen said,

    July 3, 2015 @ 7:02 am

    I am puzzled by the symbols in this discussion of pronunciations. Why are diagonals used instead of brackets to enclose phonetic values?

  4. Jerry Friedman said,

    July 3, 2015 @ 7:51 am

    I'll pronounce "apoptosis" with a silent "p" when I start hearing similar pronunciations of "Lepidoptera" and "helicopter".

  5. David L said,

    July 3, 2015 @ 7:58 am

    I came across this question sometime in the mid 1990s, when a bunch of molecular biologists were discussing it — they were about evenly split between the two options, as I recall. I think in many cases they followed the pronunciation favored by their PhD advisers.

    In other news, I remember being surprised when someone I knew pronounced 'aphelion' (the opposite of perihelion) with an 'f' sound for the ph. I had always said ap-helion, and still do, on the increasingly rare occasions when I need to say it.

  6. J.F. said,

    July 3, 2015 @ 8:00 am

    In many years working as a scientist in the US, I have always heard it pronounced ApopTOsis. It's possible that people from/trained in GB may drop the second P. I would think the original intent or pronunciation would, at this point, be secondary to being understood by fellow scientists!

  7. qroqqa said,

    July 3, 2015 @ 8:22 am

    Presumably [anthéɔ:n] in L&S could refer to flowers falling off things or things falling off flowers. And with bones, that's just another thing to worry about as we got older. There you are, L Gittlen, a proper phonetic transcription in square brackets unless the comments editor has eaten it.

    Count another vote that the medial [p] should be retained.

  8. Keith Ivey said,

    July 3, 2015 @ 8:22 am

    Do those recommending a silent p also have a silent p in helicopter because it's silent in pterodactyl?

  9. Keith Ivey said,

    July 3, 2015 @ 8:25 am

    Apologies for the redundancy. For some reason Jerry Friedman's comment wasn't displaying for me until after I posted mine.

  10. mollymooly said,

    July 3, 2015 @ 8:34 am

    Contrast "helico-pter" and "para-psychology".

  11. Eneri Rose said,

    July 3, 2015 @ 8:58 am

    As David L. found among scientists, I pronounce apoptosis with a silent second p because that is how my Anatomy and Physiology professor pronounced it – analogous to the pronunciation of ptosis.

  12. ThomasH said,

    July 3, 2015 @ 9:30 am

    Silent "p" in pterodactyl? Next you'll be telling me there's a silent "p" in psychology! :)

  13. Levantine said,

    July 3, 2015 @ 9:57 am

    Back in 1924, Fowler (following the OED) recommended pronouncing the P in words like "psychology" and "pseudo"; dropping them was apparently regarded as unscholarly.

  14. ThomasH said,

    July 3, 2015 @ 10:54 am

    One can always count on a good chap like Fowler to maintain standards [irony mark]

    [We really do need a standard irony mark.]

  15. Martin said,

    July 3, 2015 @ 10:55 am

    The other unusual pronunciation I hear frequently among immunologists and microbiologists is "macrophage" as /ˈmækɹəˌfɑʒ/ when all sources indicate /ˈmækɹəˌfeɪdʒ/.

  16. Eric P Smith said,

    July 3, 2015 @ 11:18 am

    Mark, in what way does Wiktionary's audio rendition for the UK version seem to you confusingly different from the UK IPA transcription? (I'll not put my head on the block by asserting that to me they match perfectly, until I know where the mismatch is for you!)

  17. Q. Pheevr said,

    July 3, 2015 @ 11:35 am

    I've never had occasion to pronounce apoptosis, so I remain a[g]nostic.

  18. Gregory Kusnick said,

    July 3, 2015 @ 11:56 am

    Seems to me that when coining a new technical term, if you have to add a footnote explaining that the recommended pronunciation differs from the obvious or natural pronunciation, then you ought to rethink either the recommendation or the coinage. Deliberately introducing a term that you know is going to be confusing seems like bad policy.

  19. Ken Miner said,

    July 3, 2015 @ 1:35 pm

    @ ThomasH I used suspension points ("…") as an irony mark most of my life. (Lately I don't because I'm not all that sure how many other people do. But I know no alternative.)

    I have no problem with "apoptosis", since I never have occasion to use it. My problem is with "chthonic". (For some reason Camille Paglia used this term to replace Nietzsche's "dionysian" in her _Sexual Personae_.) If I pronounce it the way dictionaries recommend – with silent "ch" – no one will have the slightest idea what I am saying.

    Lots of words seem to have emerged in the written language, leaving their pronunciation to fend for itself.

  20. cameron said,

    July 3, 2015 @ 1:51 pm

    A long time ago, at a university far far away, I wrote and recorded a song called "Cephaloptosis".

  21. D.O. said,

    July 3, 2015 @ 1:59 pm

    Though it does not have even a shred of etymological justification, if apoptosis is really complementary to mitosis, as Kerr et al. suggested, it might have sense to pronounce it with silent "p" to emphasize the relationship.

  22. Coby Lubliner said,

    July 3, 2015 @ 2:13 pm

    Is ThomasH's preference for proparoxytone based on the Greek original? The norm in English for Greek-derived words, even if changed, is to keep the stress on the syllable that would have it in Latin, not in Greek, as in SOCrates (Σωκράτης) or AESchylus (Αἰσχύλος). I don't think that words with ō (transliterating ω) in the penult can be proparoxytone in Latin.

  23. Keith Ivey said,

    July 3, 2015 @ 2:42 pm

    Parapsychology seems different because para- is a productive prefix in English. I don't think apo- is.

  24. Ray said,

    July 3, 2015 @ 3:15 pm

    the other day I was watching the news, and the journalist called it "a many-headed hydra" (referring to isis) — but he pronounced "hydra" as "heedra." so I rolled my eyes (like the time I heard a pundit pronounce "chasm" with the "ch" as in "chicken.")

    but it kept bugging me, how somebody could come up with that pronunciation of "hydra." so I googled the greek pronunciation, and it is indeed something like "heedra." so maybe the journalist knew greek. but still.

    (it happens at 3:42 in the video clip:)

  25. Stan Carey said,

    July 3, 2015 @ 3:27 pm

    if you have to add a footnote…

    @Gregory: GIF comes to mind – legions of sticklers parrot its inventor's futile insistence on /dʒɪf/.

  26. ThomasH said,

    July 3, 2015 @ 3:54 pm

    We could do "chthonic" as "[]thonic" with a "[]" from some African click language. :) On the other hand, what's the good of writing unpronounceable words if people go out and pronounce them?

    As for my preference for a proparoxytonic "apoptosis," no, it just sounds cool (and unlike a disease). BTW is "proparoxitone" proparoxitonic?

  27. Brett said,

    July 3, 2015 @ 3:55 pm

    @Keith Ivey: It's significant both that "para-" is a productive prefix and that "psychology" is a common word. ("Ptosis" is not.) I'm not sure how I would about the pronunciation if only one of those facts were true.

  28. Johannes said,

    July 3, 2015 @ 4:03 pm

    An analogous word is the stylistic device 'polyptoton'. Has anyone come across a pronunciation dropping the second 'p'? I couldn't find any examples of this in the dictionaries, and indeed would have been very surprised if I had, but you never know.

    @Ken Miner The OED at least gives /ˈkθɒnɪk/ for 'chthonic'. I agree, the pronunciation without the initial /k/ is disconcerting.

  29. Ethan said,

    July 3, 2015 @ 4:10 pm

    @Keith Ivey: But we're talking about a technical term in biology, and apo- is certainly a productive prefix in biological terminology. You can stick "apo" in front of any protein name or generic substitute to mean "without anything bound to it". E.g. apoapoenzyme, apoprotein, apohemoglobin.

    [(myl) But this isn't that apo-.]

  30. Rubrick said,

    July 3, 2015 @ 5:07 pm

    If the leading "c" is left silent in chthonic, than it should surely also be dropped in Cthulhu, but then it would be unclear to sci-fi con-goers whether someone was referring to the Great Old One or to George Takei's Star Trek character (and merely had a lisp), and all hell would break loose.

  31. Keith Ivey said,

    July 3, 2015 @ 5:14 pm

    Ethan, I think that's a different apo- prefix, even it has the same origin. It wouldn't apply to ptosis, and apoptosis is not a drooping of the eyelid with nothing bound to it. It doesn't seem like apoptosis was formed by adding the English prefix apo- to the English word ptosis. It doesn't have anything to do with the English word ptosis, except for coming from the same Greek word.

  32. Eric P Smith said,

    July 3, 2015 @ 6:06 pm

    Being from Scotland, I don't pronounce chthonic without an initial /k/: I pronounce it without an initial /x/.

  33. David Eddyshaw said,

    July 3, 2015 @ 8:30 pm

    I also have cause from time to time to actually speak the word, and when I do, I pronounce the second p; the real hardcore (UK pathologists) seem not to, though. I expect it's a status thing … in-group marker …

    Mind you, I was also taught (in Glasgow, about half a century ago) to pronounce the p in "psalm." (And the "l", naturally.) What do I know?

  34. yastreblyansky said,

    July 3, 2015 @ 8:37 pm

    @ L. Gittien: slashes used for phonemic represetations, brackets for phonetic.

  35. David Eddyshaw said,

    July 3, 2015 @ 8:41 pm

    Leave it to Psmith:,+sir?&source=bl&ots=PmoRnsvcOA&sig=33DaRniMVtlrf2xnADiYN3Ue1ag&hl=en&sa=X&ei=eDmXVZaNJ4bWU-_0p8gC&ved=0CCQQ6AEwAA#v=onepage&q=peasmith%2C%20sir%3F&f=false

  36. David Eddyshaw said,

    July 3, 2015 @ 8:53 pm

    (With due apologies to Eric Psmith, presumably a relation of the famous Ronald.)

  37. Eric P Smith said,

    July 4, 2015 @ 5:26 am

    @David Eddyshaw
    That's wonderful! I've never come across Wodehouse's Psmith. I always use the 'P', because I'm an amateur musician in Edinburgh and play a bit of organ, and there was a professional Edinburgh organist Eric Smith with whom I used to be confused. Yes, Ronald Psmith is definitely a relation in spirit, if not a veritable template.

  38. Bob Ladd said,

    July 4, 2015 @ 6:21 am

    @Stan Carey, re GIF – Similar problem with giga-. This is now clearly /g-/, not /dʒ-/, but if I remember correctly in the first Back to the Future movie (1986?) Doc talks about gigahertz or giga-something with /dʒ-/. Takes a while for Norma Loquendi to make up her mind sometimes.

  39. Jerry Clough said,

    July 4, 2015 @ 9:07 am

    When I first encountered the word (which would have been in talks around 1980) IIRC it was always pronounced with a silent second 'P'. There were several British embryologist fascinated by the role of cell death in pattern formation during the early 1980s, and it would have been listening to one of their presentations where I first heard it.

    Not having cause to use it in everyday life for around 30 years, I'd probably be inclined to lightly sound that second 'P' these days.

    Many technical terms go through a process of evolution, and often there are amusing trans-Atlantic differences. Around the same time, a restriction enzyme, Bgl, was invariably called BaGeL by US molecular biologists, and BiGgle by British ones. Sometimes these resolve themselves because one usage is superior in various ways. I found that the US term, for an embryo which started development without activation by sperm, "parthenote", was far less of a mouthful than the British "parthenogenone" (and I may have spelt this incorrectly)

  40. Tom Parmenter said,

    July 4, 2015 @ 11:36 am

    As my mother used to say, "The P is silent, as in swimming."

  41. Eric P Smith said,

    July 4, 2015 @ 2:31 pm

    @Tom Parmenter: I'm glad somebody said that, or I'd have felt it an opportunity missed.

  42. Anna Johnson said,

    July 4, 2015 @ 4:06 pm

    Wait, people don't pronounce the initial [k] in chthonic? I know it's an unusual (unique?) onset in English, but it's not difficult to say. I've never occasioned to drop the ch-, that's… I'm so confused right now.



  43. Eli Nelson said,

    July 4, 2015 @ 4:44 pm

    It's not difficult to pronounce a [p] in "psycholology" either. But the sequences aren't natural to English phonology, and there's also a historical tradition of dropping plosives like this at the start of words from Greek.

  44. Xmun said,

    July 4, 2015 @ 7:54 pm

    The Maltese for "hospital" is "sptal". I saw the word on a road sign but never heard it pronounced. Anyone know? I imagine there's a hint of a schwa between the p and the t. "Spital" is of course good obsolete English, used for example by George Herbert.

  45. mollymooly said,

    July 5, 2015 @ 7:48 am

    Contrast the first n in damning and damnation or damnable.

    The initial ch in chthonic is silent in American dictionaries and optional in British dictionaries.

    The non-silent p in ps- words in the first edition of the OED was an idiosyncrasy of Murray's.

  46. Will Leben said,

    July 5, 2015 @ 3:04 pm

    Whether to pronounce the second p in "apoptosis" is something even the medical dictionaries have differed on. With a medical colleague then at Stanford, I once looked into the problem briefly (Katsikis & Leben (1995) Apoptosis. Nature 374: 670). The best argument comes from the structurally analogous word "proptosis," where the p before t is definitely pronounced.

    The explanation is that because in English syllable-initial pt is disallowed, we pronounce "ptosis" without the p. But in "apoptosis," as in "proptosis," that p becomes the coda of the first syllable, avoiding a syllable-initial pt cluster.

    For a nice summary, see

  47. Pretty Pink Ponies said,

    July 5, 2015 @ 3:51 pm

    "The initial ch in chthonic is silent in American dictionaries and optional in British dictionaries."

    Well I reckon I don't say the p in psalms because I hear it said a lot; on the other hand, I don't say the l in psalms (or salmon) either because Southern New England.

    I'm just gonna spell it saams from now on

  48. Terry Collmann said,

    July 5, 2015 @ 5:38 pm

    Jerry Clough: "a restriction enzyme, Bgl, was invariably called BaGeL by US molecular biologists, and BiGgle by British ones" – that would be the difference between a culture familiar with Jewish culinary traditions and one much more familiar with the works of Captain WE Johns.

  49. richardelguru said,

    July 6, 2015 @ 6:50 am

    @ Tom Parmenter
    'The p is silent as in Pbath'?

  50. Jongseong Park said,

    July 6, 2015 @ 9:00 am

    @Pretty Pink Ponies, the "l" is traditionally silent in "psalms" and "salmon"; as I understand, the versions with "l" heard in certain regions of the U.S. are relatively recent spelling pronunciations.

    I've always looked at words like chthonic and hoped I would never be forced to say them out loud. I get that the traditional treatment is to simplify the initial consonant clusters that don't fit into English phonotactics by dropping the first consonant sound, but saying something like "thonic" and expecting your audience to understand it to be a word that is spelled "chthonic" seems rather demanding when these are far from everyday words.

    A sort-of similar issue in transcribing foreign terms into hangul, the Korean alphabet, is how to treat compounds where the second element starts with a consonant cluster formed from a voiceless stop followed by an obstruent (e.g. pt-, ps-, and ks-). In the middle of words, the first consonant of such clusters naturally become syllable codas, as in 헬리콥터 hellikopteo "helicopter". But due to Korean phonotactics, such clusters require the insertion of an epenthetic vowel in initial positions, as in 프시케 peusike "psyche". So how to deal with cases like "archaeopteryx"? I've seen it spelled 아르케옵테릭스 areukeopterikseu, with the -pt- dealt with as if it were any other medial cluster, but slightly more often I see it spelled 아르케오프테릭스 areukeopeuterikseu as if it were a compound of areukeo and peuterikseu. I'm not saying that this proves awareness of pteryx as an independent element, but it is a possibility.

  51. Bean said,

    July 6, 2015 @ 10:27 am

    Add one more vote for both Ps. But I learned the word from a prof who came to Canada as a draft-dodger… therefore originally American. It never occurred to me to pronounce it any other way (and I never once talked about apoptosis with the one prof of British extraction in the same department).

    In general I also (at times reluctantly) agree with the sentiment that it is more important to be understood than to be correct.

  52. Joyce Melton said,

    July 6, 2015 @ 5:58 pm

    Oddly, I've always remembered the spelling and meaning of apoptosis by the mnemonic of imagining the cell popping. Or is that nemonic?

  53. Matt McIrvin said,

    July 6, 2015 @ 11:13 pm

    Sometimes these things are more or less arbitrary and subcultural. My mother-in-law, a retired nurse, pronounces "centimeter" with the first syllable pronounced more or less as in French, like "sontimeter". I've heard that this is a medical usage, preferred particularly by surgeons.

  54. A.R.Duncan-Jones said,

    July 7, 2015 @ 4:49 am

    @Molly Mooly

    Chthonic & British Dictionaries: OED (2nd ed.) is unequivocal: kθ;
    Collins on-line θ; while MacMillan and Chambers on-line have never heard of the word.

    I would not say that meant optional, just that some dictionaries are better sourced than others. But then I would not dream of saying θɒnɪk, as people would θink I had θuddenly developed a θtutter or was being excessively demonstrative, as we modern Scots so often are. Gives me an uneasy, prickly feeling.

  55. A.R.Duncan-Jones said,

    July 7, 2015 @ 4:51 am

    Sorry: @mollymooly – words fail me.

  56. Nathan Myers said,

    July 8, 2015 @ 12:23 am

    I used to say "ap-op-TOE-sis", but have moved to "APpo-p'TOE-sis". I have found it increasingly easy to pronounce the p in words like psychology and pterodactyl, and now consider dropping it a minor vice akin to dropping the first r in February or library. That said, I draw the line at pronouncing the f in often or a long o in helicopter — the former because it would be objectively wrong (ignorant BBC newsreaders notwithstanding), and the latter from simple cowardice.

    I admit to shock at the mention of "affeelion".

  57. A.R.Duncan-Jones said,

    July 8, 2015 @ 4:35 am

    @Nathan Myers: did you mean the 't' in 'often' ? And why drop it, since the word comes from 'oft' ? Puzzzzled. (Though I agree about affeelion. Regrettably, I have never had occasion to pronounce 'apoptosis', though I suppose I should give it a try before falling off the perch.)

  58. Nathan Myers said,

    July 8, 2015 @ 9:20 am

    The word "often" does not come from "oft". It is an example, along with "doubt" and "debt", of the slapdash work of ignorantly prescriptive dictionarians. We are stuck with the spelling, now, but we are not obliged to honor it with pronunciation.

  59. Nathan Myers said,

    July 8, 2015 @ 9:22 am

    Looking back, I see I wrote "f" where I meant "t". The look almost the same on my phone screen.

  60. Stanley K. said,

    July 8, 2015 @ 4:25 pm

    Actually it is pronounced: ay-[make popping sound]-toe-siss

  61. A said,

    July 9, 2015 @ 3:51 am

    @Nathan Myers

    Happy to grovel corrected. But are you telling me I cannot trust the OED (2nd ed. – can't afford new, and someone stole all my Old English stuff) ? Or for that matter, trust American Heritage on-line ?

    Does it really come from the Danish 'tit' – or even 'aften, since one so often eats 'aftenmad' ? Or what ?

  62. Rodger C said,

    July 13, 2015 @ 7:27 pm

    I refuse to anowledge "apotosis."

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