The origins of theatre are ancient. The English words for theatre and drama have their roots in Ancient Greek, from the time of organized theatre’s first great emergence. Today, we use the word “theatre” in a variety of ways, as a place for dramatic performance, a company of players with a vision that animates them, and an occupation.
A theatre may be an elaborate structure in size, decoration, and functionality. The only requirement of a theatre is, however, an empty space with a place to act and a place to watch.
Theatre may also suggest its nature as a collaborative art by indicating the company or troupe into which its practitioners have formed themselves. Additionally, theatre may refer to a larger grouping of artists, plays, buildings, and practices that constitute, for instance, the American theatre or the Elizabethan theatre.
Finally, theatre is an occupation and avocation. As such it involves the work of many people in multiple functions. Theatre, however, holds historical and qualitative relationships to play, games, and sports that suggest its impulses originate in human nature. Theatre is also artistic work, and one that involves a quality unique in the arts, that of impersonating characters. As a performing art, theatre differs from the performances individuals may present in everyday life. As an art, it utilizes differing modes of performance, representational and presentational. It also differs from other kinds of related but recorded performance. Theatre is a live event that puts performers and audiences in an immediate and mutually affecting relationship.
(This is an excerpt from the book Theatre: Brief version by Robert Cohen)