noun
1.
a. : a genetic variant manifested by the occurrence of a skin or pelage color unlike the wild type of the animal group in which it appears and usually produced by a number of different factors interacting in accord with Mendel's laws
the silver color phase of the red fox
b. : an individual exhibiting or a pelt or skin that is the result of such a genetic variant
these foxes are all color phases
— compare mutation
2. : a seasonally variant pelage color
the drab summer color phase of the ermine