a cappella: performed without instrumental accompaniment.

arch form: a formal plan that has the high point in the middle. This means that the musical activity leads to this high point, which is usually set off by some sort of change--in dynamic level, in tempo, in key, etc.

bent pitch: stretching a pitch up or down, so that the note formed is not in the conventional (major/minor) scale.

blue note: a note from the African pentatonic scale substituted into a melody built mainly on the major scale. This usually results in a note that is lower than the one found in the conventional scale.

bridge: a musical transition that connects one section with another--for example, verse, bridge, chorus.

close harmony: occurs when the notes of the chord (or harmony) are very close in pitch to the notes of the melody. So, everyone sounds very close together, and they usually sing in the same rhythm.

consonance/dissonance: a consonance is a clear, stable harmony (chord), and a dissonance is an unsettling, unstable harmony.

crescendo/decrescendo: gradual increase/decrease in dynamic level.

fade-in, fade-out: when a song begins gradually with thin texture, after which more instruments and/or voices are added. Likewise, fade-out means that a song dies off, without coming to a definite close.

falsetto: a method of vocal production, especially in men, when a singer sings in the  very upper part of his range. The singer sings from the head, rather than from the chest to produce a lighter sound.

hook: a catchy melodic/rhythmic idea in rock music, which “hooks” the listener. A hook is often associated with lyrics, e. g., “I Heard It Through the Grapevine.” 

melisma: in vocal music, several notes sung to a single syllable of text.

modal harmonies: chords that are built from scales that are different from our normal major and minor scales.  These scales were used in music of the middle ages and are also found in some folk music.

mountain vocal sound: the flat, nasal style of singing heard in country music.

outro: the ending of a song; opposite of intro.

phrase: a musical “sentence” that is part of the melody or tune. Riffs combine to make phrases, and phrases combine to form the melody.

range: the distance from the highest to the lowest note of a song, an instrument, or a voice.

register: a section of the range. A violin plays in a high register, while a bass in in a low register.

shuffle rhythm: long-short division of the beat, as in boogie-woogie and later in R & B. The long note gets the accent.

tonic chord: the I chord (or main chord) in the key. It is very stable and provides the feeling of coming home.

trill: quick alternation between two note that are very close to one another.