There are a variety of theatrical forms used in theatre

Theatre

Theatre is a collaborative form of fine art that uses live performers to present the experience of a real or imagined event before a live audience in a specific place. The performers may communicate this experience to the audience through combinations of gesture, speech, song, music or dance...

 and drama

Drama

Drama is the specific mode of fiction represented in performance. The term comes from a Greek word meaning "action" , which is derived from "to do","to act" . The enactment of drama in theatre, performed by actors on a stage before an audience, presupposes collaborative modes of production and a...

. These include

Naturalism

Naturalism (theatre)

Naturalism is a movement in European drama and theatre that developed in the late 19th and early 20th centuries. It refers to theatre that attempts to create a perfect illusion of reality through a range of dramatic and theatrical strategies: detailed, three-dimensional settings Naturalism is a...

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Portraying life on stage with a close attention to detail, based on observation of real life.

Realism:
Portraying characters on stage that are close to real life, with realistic settings and staging.

Expressionism

Expressionism

Expressionism was a modernist movement, initially in poetry and painting, originating in Germany at the beginning of the 20th century. Its typical trait is to present the world solely from a subjective perspective, distorting it radically for emotional effect in order to evoke moods or ideas...

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Anti-realistic in seeing appearance as distorted and the truth lying within man. The outward appearance on stage can be distorted and unrealistic to portray an eternal truth.

Absurdism

Theatre of the Absurd

The Theatre of the Absurd is a designation for particular plays of absurdist fiction, written by a number of primarily European playwrights in the late 1940s, 1950s, and 1960s, as well as to the style of theatre which has evolved from their work...

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Presents a perspective that all human attempts at significance are illogical. Ultimate truth is chaos with little certainty. There is no necessity that need drive us.

Modernism

Modernism

Modernism, in its broadest definition, is modern thought, character, or practice. More specifically, the term describes the modernist movement, its set of cultural tendencies and array of associated cultural movements, originally arising from wide-scale and far-reaching changes to Western society...

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A broad concept that sees art, including theatre, as detached from life in a pure way and able to reflect on life critically.

Postmodernism

Postmodern theater

Postmodern theatre is a recent phenomenon in world theatre, coming as it does out of the postmodern philosophy that originated in Europe in the middle of the twentieth century. Postmodern theatre emerged as a reaction against modernist theatre...

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There are multiple meanings, and meaning is what you create, not what is. This approach often uses other media and breaks accepted conventions and practices.

Classical:
A type of theatre which relies upon imagination (and therefore limited props) to convey the setting and atmosphere of the play. Classical theatre usually contains lofty, grand prose

Prose

Prose is the most typical form of written language, applying ordinary grammatical structure and natural flow of speech rather than rhythmic structure...

 or free verse

Free verse

Free verse is a form of poetry that refrains from consistent meter patterns, rhyme, or any other musical pattern.Poets have explained that free verse, despite its freedom, is not free. Free Verse displays some elements of form...

 dialogue. Good examples are the Elizabethan dramatists William Shakespeare

William Shakespeare

William Shakespeare was an English poet and playwright, widely regarded as the greatest writer in the English language and the world's pre-eminent dramatist. He is often called England's national poet and the "Bard of Avon"...