look up any word, like ratchet:
 
1.
Is the condition of a cat when it can't stop meowing for a period of time. The cause is unknown.
Damn dude, my cat has meowsis, she's been making noise all night.
by Oriental Ruppunzel September 04, 2009
 
2.
The act of cats reproducing as in mitosis or meiosis with a few changes. During meowsis there is no telophase or anaphase.
My cats are performing the act of meowsis.
by fsu1000 April 19, 2011