median

(anatomy, now rare) A central vein or nerve, especially the median vein or median nerve running through the forearm and arm.

(geometry) A line segment joining the vertex of triangle to the midpoint of the opposing side.

(statistics) A number separating the higher half from the lower half of a data sample, population, or probability distribution. The median of a finite list of numbers can be found by arranging all the observations from lowest value to highest value and picking the middle one (e.g., the median of {3, 3, 5, 9, 11} is 5). If there is an even number of observations, then there is no single middle value; the median is then usually defined to be the mean of the two middle values.

(US) The area separating two lanes of opposite-direction traffic; the median strip.