Top Definition
The day that a woman gets her period, when she knows she is not pregnant.
Girl: I got my period today! I was so worried.
Girl friend: Happy Not a Mother's Day!
by toadaron June 10, 2011

Free Daily Email

Type your email address below to get our free Urban Word of the Day every morning!

Emails are sent from daily@urbandictionary.com. We'll never spam you.

×