ecrevisse vs Old World crayfish

ecrevisse and Old World crayfish both are nouns.

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

As nouns, ecrevisse and Old World crayfish are synonyms defined as:

ecrevisse and Old World crayfish: small crayfish of Europe and Asia and western North America

ecrevisse (noun)	Old World crayfish (noun)
small crayfish of Europe and Asia and western North America	small crayfish of Europe and Asia and western North America
tiny lobster-like crustaceans usually boiled briefly