Referring to a story or information that was so sensitive it should have been kept top secret, but the whole school/office knows.

Can refer to any story that didn't "leak" so much as flood, but most effectively used when referring to secret butt secks.
Bro 1- Broski, you hear 'bout dat Alexia gurl?

Bro 2-Dude, her bottom secret is bottom secret. Everyone knows what happened at that party...

Bill Clinton thought his fornication with Monica Lewinsky was private business, butt then it became bottom secret.
by Durka Durka A11ah March 15, 2011
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