orchard grass vs Dactylis glomerata

orchard grass and Dactylis glomerata both are nouns.

Word	Noun	Adjective	Verb	Adverb
orchard grass	Yes	No	No	No
Dactylis glomerata	Yes	No	No	No

As nouns, orchard grass and Dactylis glomerata are synonyms defined as:

orchard grass and Dactylis glomerata: widely grown stout Old World hay and pasture grass

Other synonyms of orchard grass include cocksfoot, cockspur.

orchard grass (noun)	Dactylis glomerata (noun)
widely grown stout Old World hay and pasture grass	widely grown stout Old World hay and pasture grass