hydroxyl radical vs hydroxyl group

hydroxyl radical and hydroxyl group both are nouns.

Word	Noun	Adjective	Verb	Adverb
hydroxyl radical	Yes	No	No	No
hydroxyl group	Yes	No	No	No

As nouns, hydroxyl radical and hydroxyl group are synonyms defined as:

hydroxyl radical and hydroxyl group: the monovalent group -OH in such compounds as bases and some acids and alcohols

Other synonyms of hydroxyl radical include hydroxyl.

hydroxyl radical (noun)	hydroxyl group (noun)
the monovalent group -OH in such compounds as bases and some acids and alcohols	the monovalent group -OH in such compounds as bases and some acids and alcohols