common osier vs osier

common osier and osier both are nouns.

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

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

common osier: willow with long flexible twigs used in basketry
osier: any of various willows having pliable twigs used in basketry and furniture

common osier (noun)	osier (noun)
willow with long flexible twigs used in basketry	any of various willows having pliable twigs used in basketry and furniture
	flexible twig of a willow tree