noon vs meridian

noon and meridian both are nouns.

Word	Noun	Adjective	Verb	Adverb
noon	Yes	No	No	No
meridian	Yes	Yes	No	No

noon (noun)	meridian (noun)
the middle of the day	an imaginary great circle on the surface of the earth passing through the north and south poles at right angles to the equator
	the highest level or degree attainable; the highest stage of development

noon (adjective)	meridian (adjective)
	of or happening at noon
	being at the best stage of development