noun. A small pyramidal-shaped section of unwashed windshield glass, which is a result of the windshield wipers not being able to reach it. It is usually located at the bottom center of the glass.
Daughter: Mom, why is that little shark fin on the window?
Mother: Oh honey, that's called a window cleft. It's there because the windshield wipers don't wipe that part.
Mother: Oh honey, that's called a window cleft. It's there because the windshield wipers don't wipe that part.
by justanothervictimoftheghetto April 13, 2010