[ burth-dey ]
/ ˈbɜrθˌdeɪ /


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.

Origin of birthday

Middle English word dating back to 1350–1400; see origin at birth, day Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for birthday

British Dictionary definitions for birthday


/ (ˈbɜːθˌdeɪ) /


  1. an anniversary of the day of one's birth
  2. (as modifier)birthday present
the day on which a person was born
any anniversary
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for birthday



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.

Online Etymology Dictionary, © 2010 Douglas Harper