common chickweed vs chickweed

common chickweed and chickweed both are nouns.

Word	Noun	Adjective	Verb	Adverb
common chickweed	Yes	No	No	No
chickweed	Yes	No	No	No

As nouns, chickweed is a hypernym of common chickweed; that is, chickweed is a word with a broader meaning than common chickweed:

common chickweed: a common low-growing annual garden weed with small white flowers; cosmopolitan; so-called because it is eaten by chickens
chickweed: any of various plants of the genus Stellaria

common chickweed (noun)	chickweed (noun)
a common low-growing annual garden weed with small white flowers; cosmopolitan; so-called because it is eaten by chickens	any of various plants of the genus Stellaria
	any of various plants related to the common chickweed