theatre [LME] The earliest theatres were the open-air theatres of the classical world, first mentioned in English in the writings of Geoffrey Chaucer. People go to the theatre to watch a play, and the word itself goes back to the Greek theasthai ‘to look at’. A theatre for surgical operations, or operating theatre, gets its name, recorded from the 1660s, because early rooms of this type were arranged like theatres, with banks of seats for observers. See also absurd.