red osier vs red willow

red osier and red willow both are nouns.

Word	Noun	Adjective	Verb	Adverb
red osier	Yes	No	No	No
red willow	Yes	No	No	No

As nouns, red osier and red willow are synonyms defined as:

red osier and red willow: Eurasian osier having reddish or purple twigs and bark rich in tannin

Other synonyms of red osier include basket willow, purple osier, purple willow, Salix purpurea.

red osier (noun)	red willow (noun)
Eurasian osier having reddish or purple twigs and bark rich in tannin	Eurasian osier having reddish or purple twigs and bark rich in tannin
common North American shrub with reddish purple twigs and white flowers