omnidirectional antenna vs nondirectional antenna

omnidirectional antenna and nondirectional antenna both are nouns.

Word	Noun	Adjective	Verb	Adverb
omnidirectional antenna	Yes	No	No	No
nondirectional antenna	Yes	No	No	No

As nouns, omnidirectional antenna and nondirectional antenna are synonyms defined as:

omnidirectional antenna and nondirectional antenna: an antenna that sends or receives signals equally in all directions

omnidirectional antenna (noun)	nondirectional antenna (noun)
an antenna that sends or receives signals equally in all directions	an antenna that sends or receives signals equally in all directions