Real Dictionary

stoat
countable noun: A stoat is a small, thin, wild animal that has brown fur. Some stoats that live in northern Europe have fur that turns white in winter.

stoat in American English
a large European ermine (Mustela erminea), esp. in its brown summer coat
noun: the ermine, Mustela erminea, esp. when in brown summer pelage

stoat in British English
noun: a small Eurasian musteline mammal, Mustela erminea, closely related to the weasels, having a brown coat and a black-tipped tail: in the northern parts of its range it has a white winter coat and is then known as an ermine