1786 as a military word, "extend (troops) in a line, expand (a unit which had been formed in columns)," from French déployer "unroll, unfold," from Old French desploiier "unfold," from Latin displicare "unfold, scatter," from dis- (see dis-) + plicare "to fold" (from PIE root *plek- "to plait"). "In its AFr. form regularly adopted in ME as desplay" [OED]. Figurative use by 1829. Intransitive sense from 1796. Related: Deployed; deploying.