Meaning

noun the value below which 50% of the cases fall

adjective 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)

adjective dividing an animal into right and left halves

originBorrowed from Middle French median, from Latin mediānus (“of or pertaining to the middle”, adjective), from medius (“middle”) (see medium), from Proto-Indo-European *médʰyos (“middle”). Doublet of mean and mizzen. Cognate with Old English midde, middel (“middle”). More at middle.

Etymology from Wiktionary, CC BY-SA 3.0