cosplay n.

1715, "style of dress," but also more broadly "custom or usage with respect to place and time, as represented in art or literature; distinctive action, appearance, arms, furniture, etc.," from French costume (17c.), from Italian costume "fashion, habit," from Latin consuetudinem (nominative consuetudo) "custom, habit, usage." Essentially the same word as custom but arriving by a different path.

It originally was an art term, referring to congruity in representation. From "customary clothes of the particular period in which the scene is laid," the meaning broadened by 1818 to "any defined mode of dress, external dress." Costume jewelry, made to be worn as an accessory to fashionable costume, is attested by 1917. Related: Costumic.

Middle English pleie, from Old English plega (West Saxon), plæga (Anglian) "quick motion; recreation, exercise, any brisk activity" (the latter sense preserved in swordplay -- Old English sweordplegan -- etc.), from or related to Old English plegan (see play (v.)).

By early Middle English it could mean variously, "a game, a martial sport, activity of children, joke or jesting, revelry, sexual indulgence." Of physical things, "rapid, brisk, or light movement," by 1620s.

Meaning "dramatic performance" is attested by early 14c., perhaps late Old English. Meaning "free or unimpeded movement, liberty and room for action," of mechanisms, etc., is from 1650s. The meaning "activity, operation" (1590s) is behind expressions such as in full play, come into play. The sporting sense of "the playing of a game" is attested from mid-15c.; that of "specific maneuver or attempt" is from 1868.

The U.S. slang meaning "attention, publicity" is by 1929. To be in play (of a hit ball, etc.) is from 1788. Play-by-play in reference to running commentary on a game is attested from 1927. Play on words "pun" is from 1798. Play-money is attested from 1705 as "money won in gambling," by 1920 as "pretend money."