c. 1300, "order or direct with authority" (transitive), from Old French comander "to order, enjoin, entrust" (12c., Modern French commander), from Vulgar Latin *commandare, from Latin commendare "to recommend, entrust to" (see commend); altered by influence of Latin mandare "to commit, entrust" (see mandate (n.)). In this sense Old English had bebeodan.
Intransitive sense "act as or have authority of a commander, have or exercise supreme power" is from late 14c. Also from late 14c. as "have within the range of one's influence" (of resources, etc.), hence, via a military sense, "have a view of, overlook" in reference to elevated places (1690s). Related: Commanded; commanding.
Command-post "headquarters of a military unit" is from 1918. A command performance (1863) is one given by royal command.
c. 1400, "an order, a command; what is commanded or ordered," from Old French comand (14c.), from comander "to order, to entrust" (see command (v.)). Meaning "control, right or authority to order or compel obedience" is from mid-15c. Meaning "power of control, mastery" (of a situation, a language, etc.) is from 1640s.