nondirectional antenna vs omnidirectional antenna

nondirectional antenna and omnidirectional antenna both are nouns.

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

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

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

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