A - The sixth note of the diatonic major scale of C. In the A minor scale (relative minor of C) it is the first note. It is the first tone in the diatonic major scale of A.

A - By: for; to; at; in.

A ballata - In the style of a simple dance.

Absolute - Absolute music. Music which is inspired by itself rather than extramusical implications such as the stories legends of "program" music.

Accelerando, accel - Gradually faster.

Accent - > placed above a note to indicate stress or emphasis.

Accidental - A sharp, flat, or natural not included in the given key.

Accompaniment - A vocal or instrument part that supports or is background for a solo part.

Adagio - Slow; slower than andante, faster than largo.

Addolorato - Sorrowfully.

Ad libitum, ad lib - A term which permits the performer to vary the tempo and/or to include or omit a vocal or instrumental part. Synonymous with a piacere.

A due - Return to unison after divisi.

Affrettando - Hurrying.

Agilmente - Lively.

Agitato - Agitated; with excitement.

Al, all', alla, alle - To; used with other words, e.g. al Fine (to the end).

Album - A full length recording. In pop music, it contains a number of songs.

Al coda - "To the coda."

Aleatory, or aleatoric music - Chance music in which the performers are free to perform their own material and/or their own manner of presentation.

Al fine - To the end.

Alla breve -  Cut time; meter in which there are two beats in each measure and a half note receives one beat.

Allargando, allarg - Slowing of tempo, usually with increasing volume; most frequently occurs toward the end of a piece.

Allegretto - Slower than allegro.

Allegro - Quick tempo; cheerful.

Al segno - Return to the sign, Dal segno.

Alteration - The raising or lowering of a note by means of an accidental.

Alto clef - The C clef falling on the third line of the staff. Most of the time is used by the viola.

Ancora - Repeat.

Andante - Moderate tempo.

Andantino - Slightly faster than andante.

A niente - To nothing, e.g. to ppp.

Animato - Animated; lively.

A piacere - Freedom in performance. Synonymous with ad libitum.

Appassionato - Impassioned.

Appoggiatura - A nonharmonic tone, usually a half or whole step above the harmonic tone, which is performed on the beat and then resolved.

Arabesque - A fanciful piano piece. Ornate passage varying or accompanying a theme.

Arpeggio - A term used to describe the pitches of a chord as they are sung or played one after the other, rather than simultaneously.

Arrache - Strong pizzicato.

Arrangement - An adaption of a composition.

Articulation - The degree to which notes are separated or connected, such as staccato or legato.

A tempo- Return to the previous tempo.

Atonality - Lacking a tonal center.

Augmentation - Compositional technique in which a melodic line is repeated in longer note values. The opposite of diminution.

Augmented - The term for a major or perfect interval which has been enlarged by one half-step, e.g. c-g, (an augmented fifth,) or c-d, (an augmented second). Also used for a triad with an augmented fifth, e.g. the augmented tonic triad in C major, C+, c-e-g.