Word Origin & History
c.1600, "area in an ancient theater," from L. orchestra, from Gk. orkhestra, semicircular space where the chorus of dancers performed, with suffix -tra denoting place + orkheisthai "to dance," intens. of erkhesthai "to go, come," from PIE *ergh- "to set in motion, stir up, raise" (cf. Skt. rghayati "trembles,
rages, raves," L. oriri "to rise"), from base *er-/*or- (cf. L. origo "a beginning;" Skt. rnoti "rises, moves," arnah "welling stream;" O.Pers. rasatiy "he comes;" Gk. ornynai "to rouse, start;" Goth. rinnan, O.E. irnan "to flow, run"). In ancient Rome, it referred to the place in the theater reserved for senators and other dignitaries. Meaning "group of musicians performing at a concert, opera, etc." first recorded 1720; "part of theater in front of the stage" is from 1768.