Theatre Glossary
Whether you're stepping on stage for the first time or picking up a script to read, here's a guide to the terms you'll encounter in the world of theatre.
299 terms
11 O'Clock Number
A showstopping musical number that occurs late in the second act of a musical, typically performed by the lead. Named after the time such songs would traditionally be performed in evening shows, these numbers deliver a final emotional peak before the finale. Famous examples include "Rose's Turn" from Gypsy and "Memory" from Cats.
Musical TheatreAbsurdism
A theatrical movement that emerged in the 1950s and 60s, exploring the idea that human existence lacks inherent meaning or purpose. Absurdist plays often feature circular dialogue, illogical situations, and characters trapped in repetitive or meaningless routines. Key playwrights include Samuel Beckett (Waiting for Godot), Eugène Ionesco (The Bald Soprano), and Harold Pinter.
Genres & StylesAct
A major division within a play, similar to chapters in a book. Most modern plays are structured in either one or two acts, though classical works often have three or five. Each act typically contains a distinct phase of the dramatic arc, with act breaks providing natural pauses for intermission and shifts in time, location, or mood.
Dramatic StructureAction Verb
A specific, playable verb that defines what an actor is doing to their scene partner in each moment—"to charm," "to threaten," "to comfort," "to provoke." Action verbs (also called "actable verbs" or "tactics") give actors concrete, physical objectives rather than vague emotional states. Playing an action verb like "to seduce" produces far more dynamic, watchable performance than simply trying to "feel romantic."
Acting & PerformanceAdaptation
The process of transforming a story from one medium into a theatrical production—a novel, film, poem, TV series, or real event reimagined for the stage. Successful adaptations find theatrical equivalents for what works in the source medium rather than simply reproducing it. War Horse adapted a children's novel with puppetry, The Curious Incident used physical theatre, and Hamilton reimagined a biography through hip-hop.
Genres & StylesAd-Lib
An improvised line or action performed during a live show that was not part of the original script. Actors may ad-lib to cover a forgotten line, respond to an unexpected event on stage, or enhance a comedic moment. While some directors encourage ad-libbing, others insist on strict adherence to the script, particularly with published texts that are under licensing restrictions.
Acting & PerformanceAgitprop
Theatre created to agitate audiences and propagandise for a political cause—typically left-wing or revolutionary. The term combines "agitation" and "propaganda" and originated in Soviet Russia in the 1920s. Agitprop uses direct, confrontational techniques: placards, chants, exaggerated characters representing social classes, and clear moral messages. While the term can be pejorative, agitprop has influenced political theatre worldwide, from Brecht to modern protest performance.
Genres & StylesAgon
A formal contest or debate between two characters in ancient Greek drama, where opposing arguments are presented in structured, often symmetrical speeches. The agon was a set piece in Greek comedy (Aristophanes used it extensively) and reflects the Greek cultural love of public debate and rhetoric. The concept has influenced all subsequent dramatic conflict—every argument scene in modern drama is, in some sense, an agon.
History & TraditionsAlarum
A stage direction found in Renaissance plays, particularly Shakespeare, indicating sounds of battle, trumpet calls, or general commotion offstage. "Alarum" (an archaic form of "alarm") signals that fighting or conflict is happening beyond the audience's view. Related stage directions include "excursions" (brief skirmishes crossing the stage) and "alarums and excursions" (extended battle sequences). These directions give modern directors creative freedom in staging.
History & TraditionsAlienation Effect
A theatrical technique developed by Bertolt Brecht (also called Verfremdungseffekt or V-effect) designed to prevent the audience from losing themselves in the story. Methods include direct address to the audience, visible stage machinery, projected titles, and actors stepping out of character. The goal is to encourage critical thinking rather than passive emotional engagement.
History & TraditionsAlto
The lowest female vocal range, also called contralto, with a rich, warm tone that sits below mezzo-soprano. In musical theatre, alto roles are often character parts—wise women, comic sidekicks, and villainesses. The alto voice brings depth and groundedness to ensemble harmonies. Notable alto roles include Madame Morrible in Wicked and Motormouth Maybelle in Hairspray.
Musical TheatreAmphitheatre
An open-air performance venue with tiered seating arranged in a curved or circular formation around a central stage area. Originating in ancient Greece and Rome, amphitheatres were designed so that the natural slope of the seating provided clear sightlines and, in the best examples, remarkable acoustics. Modern outdoor amphitheatres continue this tradition for concerts, plays, and community events.
Venues & SpacesAnagnorisis
The moment of recognition or discovery in a drama when a character passes from ignorance to knowledge—realising a crucial truth about themselves, another character, or their situation. Aristotle considered anagnorisis essential to the best tragedies. The most famous example is Oedipus discovering that he has killed his father and married his mother. The power of anagnorisis lies in its irreversibility: once known, the truth cannot be unknown.
Dramatic StructureAntagonist
A character, force, or circumstance that opposes the protagonist, creating the central conflict of the drama. The antagonist may be a villain, a rival, a social institution, or even an internal struggle within the protagonist themselves. Strong antagonists are essential to compelling drama—without meaningful opposition, there is no dramatic tension.
Dramatic StructureApron
The section of the stage that extends beyond the proscenium arch toward the audience. The apron sits in front of the main curtain, making it useful for prologues, epilogues, and intimate moments performed while a set change happens behind the curtain. In some theatres, the apron can be extended over the orchestra pit to create a thrust-style playing area.
Venues & SpacesAside
A dramatic convention where a character speaks directly to the audience or to themselves while other characters on stage supposedly cannot hear them. Asides reveal a character's private thoughts, create dramatic irony, or provide commentary on the action. Shakespeare used asides extensively, and they remain common in both classical and contemporary theatre.
Acting & PerformanceAside from the Script
When a playwright specifies that a character speaks in a register or style distinct from the rest of the dialogue—this might mean direct audience address, an internal monologue heard aloud, or a moment of heightened language within an otherwise naturalistic play. These shifts signal that the dramatic rules have temporarily changed, creating a different relationship between character and audience.
Dramatic StructureAudition
The process by which actors present themselves for consideration in a production. Auditions may involve performing a prepared monologue, cold reading from the script, singing, dancing, or a combination of these. Callbacks are follow-up auditions where directors narrow their choices. Open calls (or open auditions) are available to anyone, while invited auditions are by appointment only.
Acting & PerformanceBackdrop
A large painted cloth or scenic element hung at the back of the stage to establish the setting or environment of a scene. Backdrops can depict anything from realistic landscapes to abstract patterns. They're typically made from canvas or muslin, suspended from a batten, and can be "flown in" (lowered from the fly loft) or "flown out" (raised out of sight) during scene changes. Multiple backdrops allow rapid location changes.
Stagecraft & TechnicalBackstage
The areas of a theatre not visible to the audience, including the wings, dressing rooms, green room, and technical areas. Backstage is where actors wait for entrances, quick costume changes happen, and stage management coordinates the show. Backstage etiquette—such as staying quiet during performances—is a fundamental part of theatre culture.
Stagecraft & TechnicalBackstory
The history of a character or situation that exists before the events of the play begin. Backstory includes everything that has shaped who a character is at the start of the action—their childhood, relationships, traumas, achievements, and circumstances. While backstory may never be spoken aloud on stage, actors develop detailed backstories to inform their choices and make their characters feel like complete human beings with lives beyond the script.
Acting & PerformanceBalcony
The upper tier of seating in a theatre, located above the mezzanine or dress circle and farthest from the stage. Balcony seats are typically the least expensive in the house. Despite the distance, many theatregoers appreciate the balcony for its unobstructed overhead view of the full stage picture, particularly for visually spectacular productions.
Venues & SpacesBaritone
The male vocal range sitting between tenor and bass, offering a rich, versatile middle ground. Baritones play a wide variety of roles in musical theatre—romantic leads, antagonists, comedic characters, and father figures. The range is arguably the most common male singing voice. Notable baritone roles include Sweeney Todd, King George III in Hamilton, and Billy Bigelow in Carousel.
Musical TheatreBarn Doors
Adjustable metal flaps attached to the front of a stage lighting instrument, used to shape and control the beam of light. Barn doors typically consist of four hinged leaves (top, bottom, left, right) that can be opened or closed to block portions of the light. They provide a simple, mechanical method of preventing light spill onto areas where it isn't wanted.
Stagecraft & Technical