A theatre (spelt theater in US English) is a structure in which theatrical or dramatic works, often simply called plays, are performed. The word theatre comes from the the Greek θέατρον (theatron, meaning "place of seeing") via the French théâtre.
Legend traces the origins of drama in Ancient Greece to the sixth century BCE, when a man called Thespis (hence the use of the term thespian for actor) first added spoken parts to traditional choral and dance performances. Actors wearing masks performed outdoors at festivals in honour of Dionysos, the god of theatre, often to crowds of 12,000 or more. Nearly all Greek religious sites had a theatre used for these festivals.
The first stone theatre to be built in Ancient Greece was the Theatre of Dionysos in Athens. It was cut into the cliff face south of the Acropolis between 342 and 326 BCE, a replacement by the Athenian statesman Lykourgos of an earlier structure built of wood and earth. (What can be seen in Athens today are in fact the remains of a later rebuilding by the Romans — a much enlarged structure.)
Greek theatres were originally made up of three main parts: the ορχήστρα (orchestra), originally a circular performance space around the altar, later a (sometimes semicircular) space in which the chorus danced and the actors performed; the κοίλον or θέατρον, the tiers of seats around the orchestra, with access from above; the προσκήνιον (proscenium), backdrop and stage (which was the part of the theatre to undergo most changes over the centuries).
Elizabethan plays were mainly performed publicly in three types of venue (performances were also given in private houses and gardens): the yards of inns, open-air amphitheatres, and purpose-built playhouses. The earliest of these were the inn yards, whose layout influenced the playhouses (and the dramatic structure of many plays), and which were themselves sometimes converted into playhouses. Amphitheatres were used in summer, with acting troupes moving to indoor venues in winter.
The nineteenth century
By the nineteenth century the proscenium arch theatre had become dominant. In this design the audience sat directly facing the playing area, which was separated from the audience by an arched frame. A curtain can generally be drawn across the stage, facilitating scene changes. The nineteenth century saw an increasing range of theatrical effects as lighting, mechanical effects and scenic design became more sophisticated.
The main parts of a modern theatre
Front of house
The ticket office, refreshment areas, washroom facilities, and other areas used by the audience before entering the theatre itself.
The House or audience
The area where the audience sits. Most modern theatres have a raked audience, that is, the seating area slopes towards the stage to give all members of the audience a reasonably good view of the stage.
The playing area can be behind a proscenium arch, it can thrust into the audience, and in some instances, can be entirely surrounded by the audience.
The backstage contains much of the technical equipment of the theatre and scenery waiting to be used in different scenes.
The areas to either side of the traditional proscenium arch stage. Performers about to make an entrance can wait here unseen by the audience.