An often domesticated mammal (Mustela putorius furo) rather like a weasel, descended from the polecat and often trained to hunt burrowing animals.

The black-footed ferret, Mustela nigripes.

A diligent searcher.

To hunt game with ferrets.

(by extension) To uncover and bring to light by searching; usually to ferret out.

A tape of silk, cotton, or ribbon, used to tie documents, clothing, etc. or along the edge of fabric.