c. 1300, "unfold, spread out, unfurl" (a banner, etc.), from Old French desploiir (Modern French déployer) "unfold, unfasten, spread out" (of knots, sealed letters, etc.), from Latin displicare "to scatter," in Medieval Latin "to unfold," from dis- "un-, apart" (see dis-) + plicare "to fold" (from PIE root *plek- "to plait").
Properly of sails or flags (and unconnected to play); meaning "reveal, exhibit, expose to view" is late 14c.; sense of "reveal unintentionally, allow to be seen" is from c. 1600. Related: Displayed; displaying.
1580s, "description," a sense now obsolete, from display (v.). Meaning "exhibition, a spreading of anything to the view," commonly with a suggestion of ostentation or striving for effect, is from 1680s. Meaning "presentation of electronic signals on a screen" is from 1945 in reference to radar, by 1960 of computers. Display-window is attested by 1893.