noun
- the anniversary of a birth.
- the day of a person’s birth.
- a day marking or commemorating the origin, founding, or beginning of something.
- the festivities or celebration marking such a day or anniversary.
noun
-
- an anniversary of the day of one’s birth
- (as modifier)birthday present
- the day on which a person was born
- any anniversary
late 14c., from Old English byrddæg, “anniversary celebration of someone’s birth” (at first usually a king or saint); see birth (n.) + day. Meaning “day on which one is born” is from 1570s. Birthnight is attested from 1620s.