the squared pocket inside a pants or jeans pocket, once designed for a small watch; also called watch pocket
I discovered something interesting in a fob pocket of the old trousers.
He had loose matches in the breast pocket of his shirt and a waterproof box of matches in the fob pocket of his riding-breeches.
He pulled a great watch from its fob pocket and looked at it with absent eye.
Her hand reached around and pressed against the fob pocket which he had sewn in the belt of his skin trousers.
He said the words slowly, as he fumbled in his fob pocket, then cut them short as he found what he was looking for.