What is "wedgies"

Usage examples of "wedgies".

She had on white sharkskin slacks, a red-and-white striped jersey that fitted her like adhesive tape, and white wedgies with red laces.

I went through the closet, checking coat pockets, suitcases, handbags, and shoe boxes, one of which still contained the receipt for the red wedgies she'd been wearing the first time we met.

Annette clomped down the trailer step on her canvas wedgies and tucked her hand through Lieutenant Dolan's arm.