Any of various semiaquatic carnivores of the genus Mustela, especially M. vison of North America, resembling the weasel and having short ears, a pointed snout, short legs, and partly webbed toes.
Either of two slender-bodied semiaquatic carnivorous mammals ( of North America and of Eurasia) of the weasel family that have partially webbed feet, a rather short bushy tail, and a soft thick coat.