I
In animal husbandry, the mature female of domesticated cattle .
The name is also applied to the mature female of various, usually large, animals (e.g., elephant , whale , or moose ), or, more broadly, to any domestic bovine animal (see bovid ) regardless of gender or age.
II
[c mediumvioletred] (as used in expressions)
mad cow disease
sea cow
Steller's sea cow