crayfish vs ecrevisse

crayfish and ecrevisse both are nouns.

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

As nouns, ecrevisse is a hyponym of crayfish; that is, ecrevisse is a word with a more specific, narrower meaning than crayfish:

Other hyponyms of crayfish include Old World crayfish, American crayfish.

As nouns, crayfish and ecrevisse are synonyms defined as:

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

Other synonyms of crayfish include crawdad, crawfish.

crayfish (noun)	ecrevisse (noun)
large edible marine crustacean having a spiny carapace but lacking the large pincers of true lobsters	small crayfish of Europe and Asia and western North America
small freshwater decapod crustacean that resembles a lobster	tiny lobster-like crustaceans usually boiled briefly
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