We have the word "eve" to mean the day before a specific day, like a holiday. The day before Christmas is "Christmas Eve".
Is there a word that can be used to concisely say "the day after Christmas", such as "I disposed of my Christmas tree on Christmas XXXX"?
Edit: To clarify, I'm not concerned with Christmas specifically, but with a way to say "the day after a specific, named day". Therefore, "the second day of Christmas", while interesting, is not a valid answer to this question, unless you can also say "the second day of Presidents' Day", which — although "Presidents' Day Eve" doesn't sound a lot better, either — does not seem correct.
Best Answer
"The morrow of…"
Strictly this means "the morning of", but to talk of "the morrow" would be to talk of the coming morning, and so "the morrow" is the next day. Alas "on the morrow of Christmas" would be a tad ambiguous for this reason with it being more likely to mean Christmas morning, unless one was speaking during Christmas day.
Conversely, eve does not strictly mean "the day before" but the evening of. Since days were once reckoned from sundown to sundown, Christmas would start on what we would now consider the sundown of 24th December, and so the evening start of Christmas—Christmas Eve—happens on the day prior to the bulk of it, by the modern reckoning of dates moving upon the stroke of midnight. This goes some way to explain why some European countries have a bigger celebratory meal on the 24th than the 25, and why Hallowe'en is on the night before, rather than after All Hallows; by the old reckoning, the day had started at sundown.
"The morrow of…" is not in very common use any more. Nor for that matter is eve other than as preserved in "Christmas Eve" and the like and figurative uses like "eve of destruction".
Considering this, and the potential for considering it either as the morning during or the morning after, the simple phrase "the day after…" is much more useful.