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

The Urban Dictionary Mug

One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.

Buy the mug