meridian vs noon

meridian and noon both are nouns.

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

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

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