crow's foot vs crow's feet

crow's foot and crow's feet both are nouns.

Word	Noun	Adjective	Verb	Adverb
crow's foot	Yes	No	No	No
crow's feet	Yes	No	No	No

As nouns, crow's foot and crow's feet are synonyms defined as:

crow's foot and crow's feet: a wrinkle in the skin at the outer corner of your eyes

Other synonyms of crow's foot include laugh line.

crow's foot (noun)	crow's feet (noun)
large tree of Australasia	a wrinkle in the skin at the outer corner of your eyes
a wrinkle in the skin at the outer corner of your eyes