Any of various semiaquatic, fish-eating mustelid mammals of the subfamily Lutrinae, with short legs, webbed feet, and dense fur, able to swim with…

By confusion: a beaver; an otter. Obsolete.

(a) an otter; (b) U.S. the hellbender, Cryptobranchus alleganiensis (rare); cf. water dog, n. 3.

a mustelid mammal that hunts in water; esp. an otter.

Walton's name for: an otter, Lutra lutra.

Any of various aquatic animals. A river otter (subfamily Lutrinae). Now rare (chiefly regional).

an otter of the genus Lutra, found typically in freshwater (distinguished from the sea otter, Enhydra lutris).

‘any ordinary otter of the subfamily Lutrinæ, inhabiting rivers and lakes, as distinguished from the sea-otter, Enhydris marina’ (Cent. Dict.).

a predatory aquatic or semiaquatic animal; esp. a pike (pike, n.3 a).