medial Look up medial at Dictionary.com
1560s, "pertaining to a mathematical mean," from L.L. medialis "of the middle," from L. medius "middle," from PIE *medhjo-, from base *me- "between" (cf. Skt. madhyah, Avestan madiya- "middle," Gk. mesos, Goth. midjis, O.E. midd "middle," O.C.S. medzu "between," Arm. mej "middle"). Meaning "occupying a middle position" is attested from 1721.