10 Essential Musical Terms

Arpeggio
An arpeggio is a musical figure in which the notes of a chord are played in succession rather than at once. The term comes from an Italian verb meaning “to play the harp.” Arpeggios are a common element of minimalist music. By organizing the notes in an arpeggio into ever-changing rhythmic patterns, minimalist composers can create a great deal of musical interest even when the same notes are repeated over and over, as in the Prelude to Akhnaten.

Chord
A combination of notes that sound simultaneously, usually comprising at least three different pitches. The triad, a type of chord built from a root pitch with two thirds stacked above it, is the basic building block of tonal harmony. Chords may be consonant (in which case they sound stable and pleasant) or dissonant (in which case they sound unstable and harsh).

Chorus
A group of singers performing together. The chorus’s music can range from simple unison melodies to complex, multi-part singing with a high degree of rhythmic independence. In opera, the composer may use a chorus to represent large groups of characters, such as townspeople, soldiers, or guests at a party.

Countertenor
The highest male vocal type, with a range equivalent to a female mezzo-soprano or soprano. Countertenors have the deep speaking voices typical of adult males, but they carefully train their falsetto (“head”) range so they can sing remarkably high lines of music.

Duet
The most famous operatic musical form is the “aria,” a vocal number for solo voice, but opera is full of numbers for multiple voices, as well. Such works for “ensemble” (i.e., a group of singers) are typically labelled according to how many people are involved in the scene: A duet is for two singers, while a trio is for three singers. (One also hears about quartets, quintets, sextets, septets, octets, and even nonets—scenes for four, five, six, seven, eight, or nine singers, respectively.) Although duets are often used for love scenes in opera, they may also be used for arguments, conversations, or any other kind of scene involving two main characters.

Hemiola
A rhythmic device that superimposes or interchanges duple and triple rhythmic groupings. For instance, if one person claps twice for every click of a metronome while another person claps three times per click, the result will be a hemiola. Alternatively, if one person claps two times per metronome click and then switches to clapping three times per metronome click, this juxtaposition of duple and triple beat divisions is also called a hemiola.

Hymn
From the Greek hymnos, meaning “song of praise,” and now typically used to refer to a song in praise of a god (or gods). A broad term, “hymn” encompasses a great variety of musical styles, languages, and religious traditions. In the Roman Catholic church before the Second Vatican Council, hymns were typically sung in Latin; in contrast, Protestant hymns were typically sung in the vernacular (the language spoken by believers in their day-to-day lives).

Libretto
The text of an opera or staged musical drama, comprising all spoken words and stage directions. Literally “little book” in Italian, the word refers to the centuries-old practice of printing a small book with an opera’s text, which was available for sale prior to a performance. A related word, “librettist,” refers to the artist who creates the words for the composer to set to music, either adapting them from an existing source or writing original material. By contrast, the opera’s music in written or printed form is called a “score.”

Minimalism
A style of composition marked by a purposefully simplified melodic, rhythmic, and harmonic language. It often features lengthy repetitions and ostinatos of simple musical gestures against a static harmonic (typically diatonic) background. As a musical movement, minimalism first arose in the 1960s as a reaction against the complex atonality and fragmented musical forms of the mid-20th century. The foremost minimalist composers are Philip Glass, Steve Reich, and Terry Riley, although not all composers whose work is described as “minimalist” embrace the term.

Rhythm and Meter
Western music unfurls in time in relation to a steady pulse or beat. Whether or not this pulse is actually played (for instance, by a steady drumbeat), all durations are conceptualized, notated, and understood in relation to this pulse. “Meter” refers to how these pulses are grouped and divided (for instance, the repeating pattern of three quarter-notes that forms the basic structure of ¾ time), while “rhythm” refers to the varying durations of notes that are performed within a given meter. The interplay between different rhythms and meters gives minimalist music much of its variety and texture.