unbirthday

1 7.8

People celebrate a day that is not their birthday with a party or small gifts for fun

noun
/ʌnˈbɜrθdeɪ/

Informal

: uncumpleaños

Today, you know, is my unbirthday.

Examples

Why, my dear, today is your unbirthday too.

Alice in Wonderland (1951)
The card enclosed said: "Happy unbirthday to my favorite women."

Fiction book (1992)
Why, then, today is my unbirthday too.

Alice in Wonderland (1951)
A very merry unbirthday to us, to us

Alice in Wonderland (1951)
A very merry unbirthday to us

Alice in Wonderland (1951)
So happy unbirthday again Liz, congratulations you very much.
She doesn't know what an unbirthday is.

Alice in Wonderland (1951)
Ah, but there are 364 unbirthdays

Alice in Wonderland (1951)
Today is a special day, as we are celebrating my unbirthday with cake and gifts.
Every year, my friends throw me a party for my unbirthday just for fun.

Antonyms

birthday

∞ 1.0

A day each year when people celebrate the day they were born

How Special

milestone

108 3.2

birthday

∞ 1.0

unbirthday

Informal

1 7.8

everyday

448 1.0

Surface Forms

unbirthday singular

unbirthdays plural

Morphology

unbirthday = birthday (transparent) = un + birth + day

The prefix 'un-' negates the familiar compound 'birthday', so learners who know 'un-' and 'birthday' can readily infer 'a day that is not one's birthday'.

Etymology

Unbirthday is formed from the prefix un- 'not' and birthday, so it literally means a day that is 'not' your birthday. The idea was popularized by Lewis Carroll in his Alice stories as a playful celebration, so an unbirthday is any ordinary day you choose to make special for fun.