greengage plum vs greengage

greengage plum and greengage both are nouns.

Word	Noun	Adjective	Verb	Adverb
greengage plum	Yes	No	No	No
greengage	Yes	No	No	No

As nouns, greengage plum and greengage are synonyms defined as:

greengage plum and greengage: sweet green or greenish-yellow variety of plum

greengage plum (noun)	greengage (noun)
sweet green or greenish-yellow variety of plum	sweet green or greenish-yellow variety of plum