accent

A dynamic effect that places an emphasis on a note or chord.

accidentals

Symbols in written music to raise ( = sharpen) or lower ( = flatten) notes by semitones. A double flat (() lowers the pitch by a tone. A natural () cancels the accidental alteration.

acoustic guitar

A hollow-bodied guitar that does not require electronic amplification.

action

The strings' playability along the neck. Action is affected by the strings' distance from the neck, the neck straightness, and the string gauge.

active pickups

Pickups that use a battery going directly to the pickup to boost the sound.

altered chord

A chord or scale in which one or more of the notes is changed to a note not normally associated with that scale.

arch-top

A guitar, often an acoustic, with a curved top (sound-board) and F-holes similar to a violin's.

arpeggio

Literally, “like a harp” — that is, playing the notes of a chord one after the other rather than together. Also known as a broken chord.

articulation

The characteristics of attack and decay of single or groups of notes. For example, “staccato” and “legato” are types of articulations.

artificial harmonics

Harmonics produced by fingering a note on the frets and lightly touching the string a fourth higher.

atonal

Not part of the tonal system of major and minor keys; in no key at all.

attack The characteristics of the beginning of a sound.

augmented

Intervals increased by a semitone are known as augmented intervals. The augmented chord is a major chord with the fifth raised a semitone. (See also diminished.)