The theater is at once the art of the representation of a drama or a comedy, a particular literary genre, and the building in which theatrical performances take place. We also talk about dramatic genre.

Formerly, the word in ancient Greek: θέατρον, also designated the stage or the plateau, that is to say all the part hidden to the public by the curtain.

Figuratively speaking, « theater » refers to a place where a major activity takes place (for example, a theater of military operations).

Today, at the time of the so-called multidisciplinary arts, the definition of the art of theater is becoming wider (to be confused with the expression live show), so that some great directors do not hesitate to say that for there to be theater, it is enough to have a place, a time, an act and an audience.

These are performances in which actors / actors, put in the circumstances and situations created by a text and the vision of a director / director, embody characters for an external view (the audience), in a time and limited space. Written dialogues are called plays, but there can also be drama without written text or even without speech. There are also musical theater works, the genre being particularly represented in the famous Broadway neighborhoods in the United States or the West End in London, but also more and more around the Grands Boulevards in Paris.

In contemporary creation, the boundaries between the various performing arts (theater, mime, circus, dance …) are becoming increasingly tenuous, so that some professionals do not hesitate to replace the word theater with the words pluridisciplinary show or live performance, thus emphasizing the mixing of disciplines