median vs mesial

median is a noun but mesial is not a noun.

Word	Noun	Adjective	Verb	Adverb
median	Yes	Yes	No	No
mesial	No	Yes	No	No

median (noun)	mesial (noun)
the number midway between the two middle numbers in a series containing an even or odd number of items

median (adjective)	mesial (adjective)
relating to or situated in or extending toward the middle	being in or directed toward the midline or mesial plane of the body
dividing an animal into right and left halves
relating to or constituting the middle value of an ordered set of values (or the average of the middle two in a set with an even number of values)