marrow squash vs vegetable marrow

marrow squash and vegetable marrow both are nouns.

Word	Noun	Adjective	Verb	Adverb
marrow squash	Yes	No	No	No
vegetable marrow	Yes	No	No	No

As nouns, marrow squash and vegetable marrow are synonyms defined as:

marrow squash and vegetable marrow: any of various squash plants grown for their elongated fruit with smooth dark green skin and whitish flesh

Other synonyms of marrow squash include marrow.

marrow squash (noun)	vegetable marrow (noun)
any of various squash plants grown for their elongated fruit with smooth dark green skin and whitish flesh	large elongated squash with creamy to deep green skins
	any of various squash plants grown for their elongated fruit with smooth dark green skin and whitish flesh