meridian vs meridional

meridian is a noun but meridional is not a noun.

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

meridian (noun)	meridional (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 highest level or degree attainable; the highest stage of development

meridian (adjective)	meridional (adjective)
of or happening at noon	of or relating to a meridian
being at the best stage of development	located in the south or characteristic of southern people or places