Pertaining to or situated in the middle; specifically, in anatomy and zoology, intermediate as dividing the body by a longitudinal and vertical plane: medial; mesal: as, the linea alba is the median line of the abdomen; in botany, situatedin or along, or belonging to, the middle of a structure having a right side and a left. See below.In crystal., same as mean line and bisectrix. See bisectrix, 1.In climatology, the average central course of a trade-wind.In botany, a nerve traversing the middle of a leaf or leaf-like expansion.In botany, of a flower or other lateral structure of a plant, a vertical plane which bisects the anterior and posterior sides, and which, if prolonged, would pass through the center of the parent axis. Goebel. Also called anteroposterior plane.In entomology, the third main longitudinal vein or rib of an insect's wing, counting from the anterior border.Of or pertaining to Media, an ancient kingdom of Asia. Also Medic.n. Same as Mede.Noting the middle number of a series; having as many before as behind (or above as below) a certain number: distinguished from average: as, the median age of the population was found to be 21 (that is, there were as many persons above 21 as below it), while the average age was found to be 25.Such a point on the x -axis of the frequency polygon that the ordinate from it bisects the polygon of rectangles or the continuous curve.n. In geometry: A sect whose endpoints are the bisection-points of opposite sides of a quadrilateral.n. A sect from a vertex of a triangle to the bisection-point of the opposite side.n. The measure or observation which has as many of the separate measures or observations above as below it.n. In entomology, the median vein of an insect's wing.