hypanthium vs floral cup

hypanthium and floral cup both are nouns.

Word	Noun	Adjective	Verb	Adverb
hypanthium	Yes	No	No	No
floral cup	Yes	No	No	No

As nouns, hypanthium and floral cup are synonyms defined as:

hypanthium and floral cup: the cuplike or ringlike or tubular structure of a flower which bears the sepals and stamens and calyx (as in Rosaceae)

Other synonyms of hypanthium include calyx tube.

hypanthium (noun)	floral cup (noun)
the cuplike or ringlike or tubular structure of a flower which bears the sepals and stamens and calyx (as in Rosaceae)	the cuplike or ringlike or tubular structure of a flower which bears the sepals and stamens and calyx (as in Rosaceae)