noun

1. in ancient Greek theaters, the semicircular space in front of the stage, used by the chorus
2. in modern theaters, the space in front of and below the stage, where the musicians sit
   in full orchestra pit
3. ☆
   1. the section of seats on the main floor of a theater, esp. the front section
   2. the main floor of a theater
4. 1. a usually large group of musicians playing together; often, specif., symphony orchestra
   2. the instruments of such a group

Etymology: L < Gr orchēstra < orcheisthai, to dance < IE base *ergh-, extension of base *er-, swift movement, a raising > Sans *ṛghāyati, (he) rages, Ger arg, bad