Theatre Terms
As a service to the theatre community, AACT provides over 1000 definitions of theatrical terms. Fully searchable, our glossary is helpful for technical staff, directors, actors, producers, or anyone wanting to better understand the inner workings of theatre.
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Click on a letter (A-Z) below to find terms beginning with the specified letter, OR enter a word in "Search for Term" OR search by entering a word in "Words in Definition." For example, entering the word "curtain" would display all words whose definition includes that word. (Note: If the A-Z or word search has been activated, it must be reset before using "Search for Term" or "Words in Definition." To reset the A-Z search: Click Here)
| Term | Definition | Link |
|---|---|---|
| IRIS | Adjustable aperture which, when placed in the gate of a profile instrument, varies the size of a beam of light. Originally, iris diaphragm. | |
| IRISING | Using the adjustable aperture on a lighting instrument to reduce the size of the light beam hitting the stage. If the aperture permits it, the size of the beam can be made quite small (referred to as "the button", or closed altogether. | |
| JACK | Segmented audio connector. Mono Jacks have two connections - tip and sleeve, and are unbalanced. Stereo jacks have three connections - tip, ring and sleeve. B-type jacks (also known as Bantam jacks) were originally designed for use in telephone exchanges and provide a high quality (and expensive) connection in jackfields. A-type jacks are cheaper and more common, but more fragile. A type jacks are available in 2 sizes : quarter inch and eighth inch. | Jack |
| JACK KNIFE STAGE or JACKKNIFE STAGE | A stage used for rapid scene-shifting, consisting of a platform or two on casters, pivoted at one corner to swing off- and onstage. Thus, jackknife set. | |
| JACOBEAN DRAMA | The English drama of the reign of James I (1603-1625), sometimes extended to 1642. | |
| JUMPER | An adapter from one type of electrical connector to another. Also applicable to sound cables. | |
| JUVENILE | The role of a young man; also an actor who plays such a role. The female equivalent is "ingénue." | |
| KELVIN | The color temperature of a light source is the temperature of an ideal black-body radiator that radiates light of comparable hue to that light source. The temperature is conventionally stated in units of absolute temperature, known as Kelvin (K). Higher color temperatures (4600K or more) are called daylight colors which appear blue-white. Mid-range color temperatures (3100K–4600K) look cool white. Lower color temperatures (up to 3000K) are called warm white colors, and range from red to yellowish-white in tone. | |
| KEY LIGHT | The dominant light source/direction in a lighting state. In a sunny drawing room, the key light would be through the window, for a naturalistic exterior scene the direction of the key light could change as the sun progressed across the sky. | |
| KILL | To switch off (a light/sound effect); to strike/remove (a prop). | |
| KILOWATT | 1 kilowatt (1kW) is equal to 1000 Watts. | |
| KLIEG LIGHT or KLIEGLIGHT | Not used much today, but often referring to any powerful spotlight unit. Originally, a carbon arc spotlight developed by John and Anton Klieg, and used extensively in Hollywood. | |
| L | Abbreviation of left, meaning stage left, and seen in stage directions, either alone or in combination with other abbreviations, as in DSL(down stage left). | |
| L.D. or LD | Lighting Designer | |
| LADDER | Non-climbable structure in the shape of a ladder from which instruments can be hung in a vertical "stack." | |
| LAMP | 1) General term for unit of lighting equipment including spotlight, flood etc. 'Instrument' is more common in the U.S. (where 'lamp' often refers to what the uninitiated would call the 'bulb'), but both terms being replaced by the internationally recognized "luminaire." 2) A light source, but sometimes used to refer specifically to the "bulb" in a stage lighting instrument. | |
| LASER | Acronym for Light Amplification by Stimulated Emission of Radiation. A very high energy beam of light that remains virtually parallel throughout its length. Visible in the air only when a haze of smoke or dust is introduced. Great care is required when using lasers as this energy can cause permanent damage to the retina of the eye. | |
| LASH | To pull two flats together, edge to edge, by winding a lash line over lash line cleats in back. | |
| LASH CLEAT | ||
| LASH LINE | A rope line used to fasten flats or other scenic units to one another. |
