acorn cup vs cupule

acorn cup and cupule both are nouns.

Word	Noun	Adjective	Verb	Adverb
acorn cup	Yes	No	No	No
cupule	Yes	No	No	No

As nouns, acorn cup and cupule are synonyms defined as:

acorn cup and cupule: cup-shaped structure of hardened bracts at the base of an acorn

acorn cup (noun)	cupule (noun)
cup-shaped structure of hardened bracts at the base of an acorn	a sucker on the feet of certain flies
	cup-shaped structure of hardened bracts at the base of an acorn