12/8 groove: The slowest blues pattern in which the bass note plays on beats one and three and the chords play on beats two and four.

12-bar blues: By far the most popular form for the blues, created by following a 12-bar blues pattern of three lines per verse, with the first line repeated.

7th chord: A chord created from the altered or unaltered first, third, fifth, and seventh notes of a scale; 7th chords have a complex, bluesy sound.

accent: A musical notation (>) indicating that a note should be played louder than the rest of the notes.

accidentals: A musical notation indicating that a note should be played a half or whole step higher or lower; accidentals include flats (b), double flats (bb), sharps (#), double sharps (x), and naturals.

acoustic-electrics: A type of hybrid guitar that is an acoustic guitar with built-in pickups and electronics.

active electronics: Electric guitar electronics that have a built-in power source.

alternate picking: A combination of upstrokes and downstrokes that enables the guitarist to play faster and is the key for playing fast leads smoothly.

alternation: A musical pattern in which you alternate between playing the melody and bass parts one at a time instead of at the same time.

arpeggio: The notes of a chord played one after the other instead of simultaneously.

articulation: The way in which a musician plays and connects notes to create a distinct tonal quality, as well as distortion of the tone.

attack: The initial distinguishing sound of a note.