byname vs nickname

byname and nickname both are nouns.

Word	Noun	Adjective	Verb	Adverb
byname	Yes	No	No	No
nickname	Yes	No	Yes	No

As nouns, byname and nickname are synonyms defined as:

byname and nickname: a familiar name for a person (often a shortened version of a person's given name)

Other synonyms of byname include cognomen, moniker, sobriquet, soubriquet.

byname (noun)	nickname (noun)
a familiar name for a person (often a shortened version of a person's given name)	a familiar name for a person (often a shortened version of a person's given name)
	a descriptive name for a place or thing

byname (verb)	nickname (verb)
	give a nickname to