Real Dictionary

walrus
countable noun: A walrus is a large, fat animal which lives in the sea. It has two long teeth called tusks that point downwards.

walrus in American English
a massive, arctic sea carnivore (Odobenus rosmarus) of the same family (Otariidae) as the eared seals, having two tusks projecting from the upper jaw, a thick mustache, a very thick hide, and a heavy layer of blubber
of, characteristic of, or suggestive of a walrus; specif., designating a mustache with long, drooping ends
noun: a large marine mammal, Odobenus nosmarus, of arctic seas, related to the seals, and having flippers, a pair of large tusks, and a tough, wrinkled skin

walrus in British English
noun: a pinniped mammal, Odobenus rosmarus, of northern seas, having a tough thick skin, upper canine teeth enlarged as tusks, and coarse whiskers and feeding mainly on shellfish: family Odobenidae