Top Definition

Square root day is a humorous holiday celebrated on dates where the day and the month are both the square root of the last two digits in the current year.

For example, the last square root day was March 3, 2009 (3/3/09), and the next square root day will be April 4, 2016 (4/4/16).

by xxhowwiexx
March 03, 2009