orchestra: [17] In ancient Greece, the term orkhéstrā denoted a ‘semicircular space at the front of a theatre stage, in which the chorus danced’ (it was a derivative of the verb orkheisthai ‘dance’). English originally took it over (via Latin orchēstra) in this historical sense, but in the early 18th century orchestra began to be used for the ‘part of a theatre where the musicians played’, and hence by extension for the ‘group of musicians’ itself. The derivative orchestrate [19] was adapted from French orchestrer. [orchestra etymology, orchestra origin, 英语词源]