tortoiseshell vs calico cat

tortoiseshell and calico cat both are nouns.

Word	Noun	Adjective	Verb	Adverb
tortoiseshell	Yes	No	No	No
calico cat	Yes	No	No	No

As nouns, tortoiseshell and calico cat are synonyms defined as:

tortoiseshell and calico cat: a cat having black and cream-colored and yellowish markings

Other synonyms of tortoiseshell include tortoiseshell-cat.

tortoiseshell (noun)	calico cat (noun)
a cat having black and cream-colored and yellowish markings	a cat having black and cream-colored and yellowish markings
brilliantly colored; larvae feed on nettles
the mottled horny substance of the shell of some turtles