look up any word, like cunt:
 
1.
Genetics.
When genes croos over from.. UGH YOU WOULDN'T UNDERSTAND!
homoglobous chromosomes cross over
by AbsoluteR February 15, 2005
 
2.
When a teacher goes from being cool to not cool. Any kind of jumper or vest or bright colored blazer would be a symptom of crossing over
Mrs. Dante had the coolest shirt on yesterday and now she is wearing a jumper with letters all over it, she must have crossed over
by Harriet Potter September 23, 2004