Real Dictionary

beaver
countable noun: A beaver is a furry animal with a big flat tail and large teeth. Beavers use their teeth to cut wood and build dams in rivers.
uncountable noun: Beaver is the fur of a beaver.

beaver in American English 2
noun: a piece of plate armor for covering the lower part of the face and throat, worn esp. with an open helmet, as a sallet or basinet

beaver in American Englishfor 1, esp collectively 1
intransitive verb: to work very hard or industriously at something
noun: a large, amphibious rodent of the genus Castor, having sharp incisors, webbed hind feet, and a flattened tail, noted for its ability to dam streams with trees, branches, etc

Beaver in British English
noun: a member of a Beaver Colony, the youngest group of boys (aged 6–8 years) in the Scout Association

beaver in British English 1
noun: a large amphibious rodent, Castor fiber, of Europe, Asia, and North America: family Castoridae. It has soft brown fur, a broad flat hairless tail, and webbed hind feet, and constructs complex dams and houses (lodges) in rivers
verb: to work industriously or steadily

beaver in British English 2
noun: a movable piece on a medieval helmet used to protect the lower part of the face

beaver in British English 3
noun: the female genitals