A: 1. The musical pitch relating to 440 oscilations per second of vibration, or any octave transposition of that pitch. 2. The key of A. The sixth note (submediant) of the C major scale, and the first note of its relative minor scale.
Absolute Music: Music without associations outside of itself, in contrast to program music; music which is inspired by itself rather than extramusical implications such as the stories legends of "program" music.
Absolute Pitch: see perfect pitch.
A Cappella: "In the manner of the chapel", "as in the church". Sung music without instrumental accompaniment.
Accelerando, accel: Gradually faster.
Accent: Placed above a note to indicate stress or emphasis.
Accompaniment: A vocal or instrumental part that supports the primary part, or provides background for a soloist.
Achromatic: See diatonic.
Achtel: German; Eighth note.
Acoustics: 1. The science relating to the creation and dissipation of sound waves. 2. The way in which sound production is affected by the physical properties of the room or chamber in which they are produced.
A due: 1. Italian; musical direction meaning "for two", usually abbreviated "a2" In French, à deux. 2. Indicates that two instruments playing the same part or score are to play in unison.
Adagio: Slow; slower than andante, faster than largo.
Agitato: Agitated; with excitement.
Air: A song or melody.
Alberti Bass: A pattern of bass notes that outlines the chord being sounded in the pattern low-high-middle-high.
Albumblatt: (Ger.) A page or leaf from a book, or a short, easy piece.
Alla breve: (It. - according to the breve) Cut time; meter in which there are two beats in each measure and a half note receives one beat; twice as fast as normal.
Allemande: (Fr.) "German." A stately 16th-century German dance, initially in a duple meter. During the 17th and 18th centuries, it was used as the first movement of the suite.
Altered Chord: A chord in which a note has been changed from its normal position, usually chromatically.
Analysis: The study of the form and structure of music.
Andante: Moderate tempo.
Anthem: A choral or vocal composition, often with a religious or political lyric, with or without accompaniment, written either for performance in a church, or another place with significance to the song itself.
Arietta: A short aria.
Arpeggio: The notes of a chord played in successsion to one another, rather than simultabniously. A broken chord.
Arrangement: An adaptation of a given composition into a form other than as originally composed.
Ars Antiqua: "Old Art", "ancient art". Refers to the old musical practices of Europe during the 12th and 13th centuries, characterized by adding harmonies to chants. Also known as organum; a form of singing in three-part harmony.
Ars Nova: "New Art". A term invented by Philippe De Vitry to describe the music of his era, the 14th century, as opposed to the music of earlier generations, and saw the invention of modern notation.
Art Song: A serious vocal composition, generally for voice and piano. Denotes a self-contained work, as opposed to an aria.
Atonal: Music that lacks a tonal center, or in which all pitches carry equal importance. Wikipedia article on Atonality.
Augmentation: The lengthening of note values used in a theme to alter the melody without changing the pitches.
Augmented: Raised, or enlarged. Generally refers to the raising of a pitch chromatically by one half step.
Augmented Sixth Chord: A chord which contains an augmented sixth above the bass, in addition to various other tones, which determine weather the chord is a German Sixth Chord, French Sixth Chord, Italian Sixth Chord, Neopolitan Sixth, or Doubly Augmented Sixth Chord.