azo group vs azo radical

azo group and azo radical both are nouns.

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

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

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

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