Editing 20th Century Music Theory (section)

== <span style="color: #FFFFFF;">Remembering</span> ==
* '''Atonality''' — Music that lacks a tonal center or key.
* '''Twelve-Tone Technique (Serialism)''' — A method of composition where all 12 notes of the chromatic scale are treated as equal, usually arranged in a "Tone Row."
* '''Tone Row''' — A specific ordering of the 12 chromatic notes used as the basis for a serial composition.
* '''Polytonality''' — The simultaneous use of two or more keys.
* '''Minimalism''' — A style using repetitive patterns, steady pulses, and gradual changes (e.g., Steve Reich, Philip Glass).
* '''Aleatory (Chance) Music''' — Music where some element of the composition is left to chance (e.g., John Cage).
* '''Musique Concrète''' — Music constructed by mixing recorded sounds (natural or man-made).
* '''Electronic Music''' — Music created using electronic oscillators, synthesizers, and computers.
* '''Microtonality''' — Using intervals smaller than a semitone.
* '''Polyrhythm''' — The simultaneous use of two or more conflicting rhythms.
* '''Cluster Chord''' — A dissonant chord consisting of at least three adjacent notes in a scale.
* '''Pitch Class Set Theory''' — A mathematical way of analyzing groups of notes (sets) in atonal music.
* '''Total Serialism''' — Applying the rules of serialism not just to notes, but to rhythm, volume, and articulation.
* '''Extended Technique''' — Using an instrument in a non-traditional way (e.g., playing inside a piano).
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