herbs mercury vs herb mercury

herbs mercury and herb mercury both are nouns.

Word	Noun	Adjective	Verb	Adverb
herbs mercury	Yes	No	No	No
herb mercury	Yes	No	No	No

As nouns, herbs mercury and herb mercury are synonyms defined as:

herbs mercury and herb mercury: Eurafrican annual naturalized in America as a weed; formerly dried for use as a purgative, diuretic or antisyphilitic

Other synonyms of herbs mercury include boys-and-girls, Mercurialis annua.

herbs mercury (noun)	herb mercury (noun)
Eurafrican annual naturalized in America as a weed; formerly dried for use as a purgative, diuretic or antisyphilitic	Eurafrican annual naturalized in America as a weed; formerly dried for use as a purgative, diuretic or antisyphilitic