Tit Window 

(noun) The gap created in a button-down blouse when a chick slumps forward allowing you to see her bra and varying degrees of her cleavage.

Dude, she was sporting some serious tit window... and wearing a Hello Kitty bra.

Tit Window by aezrael June 1, 2009

Tit Window 

An otherwise normal woman's shirt with a completely pointless hole in the middle, below the neckband, specifically designed to display her cleavage. Not to be confused with a regular low-cut shirt.

It's fine to wear short shorts and a tank top and say you aren't asking for attention, but if you say the same thing while wearing a shirt with a tit window you need to shut the fuck up.

Tit Window by AntonioCastagnoli September 9, 2016