noun a photograph revealing at least a part of a woman's nipple. The premise is that the reveal is accidental; major usage of the term on Internet photograph sites US, 2004
nip slip
slang The exposure of a woman's nipple, usually accidentally. I can't believe I had a nip slip in front of all those people—it was so mortifying!With the way every celebrity nip slip gets plastered all over the Internet these days, I can't afford to not wear undergarments—ever!