Source : Webster's Revised Unabridged Dictionary (1913)

Medial \Me"di*al\, a. [L. medialis, fr. medius middle: cf. F.
   m['e]dial. See {Middle}.]
   Of or pertaining to a mean or average; mean; as, medial
   alligation.

Medial \Me"di*al\, n. (Phonetics)
   See 2d {Media}.

Source : WordNet®

medial
     adj 1: dividing an animal into right and left halves [syn: {median}]
     2: relating to or situated in or extending toward the middle
        [syn: {median}]