azo radical vs azo group

azo radical and azo group both are nouns.

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

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

azo radical and azo group: the bivalent group -N=N- united to two hydrocarbon groups

azo radical (noun)	azo group (noun)
the bivalent group -N=N- united to two hydrocarbon groups	the bivalent group -N=N- united to two hydrocarbon groups