ecrevisse vs crayfish

ecrevisse and crayfish both are nouns.

Word	Noun	Adjective	Verb	Adverb
ecrevisse	Yes	No	No	No
crayfish	Yes	No	No	No

As nouns, crayfish is a hypernym of ecrevisse; that is, crayfish is a word with a broader meaning than ecrevisse:

Other hypernyms of ecrevisse include crawdad, crawdaddy, crawfish.

As nouns, ecrevisse and crayfish are synonyms defined as:

ecrevisse and crayfish: tiny lobster-like crustaceans usually boiled briefly

Other synonyms of ecrevisse include crawdad, crawfish.

ecrevisse (noun)	crayfish (noun)
small crayfish of Europe and Asia and western North America	large edible marine crustacean having a spiny carapace but lacking the large pincers of true lobsters
tiny lobster-like crustaceans usually boiled briefly	small freshwater decapod crustacean that resembles a lobster
	tiny lobster-like crustaceans usually boiled briefly
	warm-water lobsters without claws; those from Australia and South Africa usually marketed as frozen tails; caught also in Florida and California