Definitions by internet comedian

a Plank 

used to refer to a flat-chested female with small posterior booty, as well!

{a Plank] is used to refer to a flat-chested female with small posterior booty, as well!

Look at her, if she turns sideways it looks like
she has two backs. She looks like a wooden plank!

a Plank by internet comedian December 11, 2019