- any of several aquatic, furbearing, weasellike mammals of the genus Lutra and related genera, having webbed feet and a long, slightly flattened tail.
- the fur of an otter.
- (in the Volsunga Saga) a son of Hreidmar, who assumed the form of an otter when fishing, and who was killed by Loki while in that form.
- any freshwater carnivorous musteline mammal of the subfamily Lutrinae, esp Lutra lutra (Eurasian otter), typically having smooth fur, a streamlined body, and webbed feet
- the fur of any of these animals
- a type of fishing tackle consisting of a weighted board to which hooked and baited lines are attached
- to fish using an otter
