Charlie Clingen writes:
This year I have started to notice an ambiguous use of the terms Christmas Eve and New Year’s Eve. In the good old days, it seems to me that those terms commonly were used to mean the evening of the day before Christmas Day/New Year’s Day. Now, in addition to those meanings, I have been hearing them used to mean the entire day before Christmas Day and New Year’s Day, especially in weather forecasts and financial news. Are the terms Christmas Eve Day and New Year’s Eve Day becoming less popular? I admit it does save a few bits here and there; maybe the occasional ambiguity is worth it.
This may be an instance of the Recency Illusion. At least, the second sense for eve in the OED is glossed "The evening, and hence usually the day before a Saint's day or other church festival. Hence gen. the evening, or the day, before any date or event", with citations back to 1290, at least some of which clearly refer to the whole preceding day:
a1662 BP. B. DUPPA Rules to Devotion (J.), Let the immediate preceding day be kept as the eve to this great feast.
At about 2:00 am Christmas Eve morning, a man stopped to give a woman a ride near Northern Lights and Old Seward Highway.
The Senate reached a milestone in passing health care reform early Christmas Eve morning …
Some area drivers will have to navigate slick roads if they're headed to work Christmas Eve morning.
A weak coastal storm threatens a light mix of precipitation late tonight into New Year's Eve morning.
The game will take place on New Year's Eve morning, Thursday December 31, at 11am.
In contrast, in all the past history of English literature, at least as recorded by LION, the string "eve morning" occurs exactly once, in a 1983 poem by Jenny Joseph, "Beyond Descartes", which contains the line
113 Christmas Eve morning—a paradox of words
And the Google News Archive graphs for "Christmas Eve morning" vs. "Christmas Eve" suggest a meaningful recent increase in usage of the former, just as Charlie suggests:
(That lonesome datapoint in 1902 is from the Chicago Tribune: "Thackeray was only 52 years of age that sad Christmas eve morning when he was found dead in his bed.")
As for "Christmas Eve day" and "New Year's Eve day", they don't seem to have a very different history. English literature is entirely innocent of any instance of either expression, according to LION. The Google News Archive timeline for "Christmas Eve day" looks roughly similar to that of "Christmas Eve morning":
The "__ Eve day" expressions seem to be roughly as frequent in current usage as the "__ Eve morning" expressions. (I'm not sure what accounts for the odd Google News numbers for New Year's Eve day vs. morning — vagaries of current weather reports?)
|Google News||COCA||LDC News|
|Christmas Eve morning||267||14||19|
|Christmas Eve day||228||5||28|
|New Year's Eve morning||917||2||5|
|New Year's Eve day||10||6||13|
I'll leave it to others to track down "Christmas Eve day morning", "the morning of Christmas Eve (day)", and recursive constructions like "New Year's Eve Eve", and just join Charlie in wishing everyone
Happy New Year’s! (all three: eve day, eve, and day)