10 Essential Opera Terms

Aria
A song for solo voice accompanied by orchestra. In opera, arias mostly appear during a pause in dramatic action when a character is reflecting on his or her emotions. Most arias are lyrical, with a tune that can be hummed, and many arias include musical repetition. For example, the earliest arias in opera consist of music sung with different stanzas of text (strophic arias). Another type of aria, the da capo aria, became common by the 18th century and features the return of the opening music and text after a contrasting middle section. 19th-century Italian arias often feature a two-part form that showcases an intensification of emotion from the lyrical first section (the cavatina) to the showier second section (the cabaletta).

Chorus
A section of an opera in which a large group of singers performs together, typically with orchestral accompaniment. Most choruses include at least four different vocal lines, in registers from low to high, with multiple singers per part. The singers are typically from a particular group of people who play a certain role on stage—soldiers, peasants, prisoners, and so on. Choruses may offer a moral, comment on the plot, or participate in the dramatic action.

Deus ex machina
Literally “god from the machine,” a term describing a denouement in an opera or play when a god appears and helps solve any remaining conflicts. In ancient Athens, the appearance of the god was affected through the use of a mechanical crane. In Baroque opera, a king or nobleman would often appear in the role of the god, implying both their own ability to solve problems affecting their populace and referencing their supposedly divine position.

Diminished chord
A chord consisting of stacked minor thirds. A profoundly dissonant chord, the diminished chord has long been associated with a somber or frightening mood in music—especially since it always contains a tritone (the “devil’s interval”).

Motif
A short, recurring musical phrase that, in opera, can be paired with a specific person, place, idea, or emotion, and then used to wordlessly express those ideas. In many cases, motifs are melodic, like the “Children’s Theme” from Medea’s Act III aria, but they can also be harmonic or rhythmic. More complex and strict systems of motifs include the German leitmotif, associated with Wagner, and the French idée fixe, associated with Hector Berlioz, both of which were popular in the 19th century.

Obbligato
A solo instrumental line, often featuring a distinctive timbre, that is part of the accompaniment in a vocal work. Obbligato (“obligatory”) lines appear only when there is at least one other instrument providing the basic accompaniment, and although subsidiary to the vocal line, it clearly stands out against the rest of the accompaniment. Although the notion of an obligatory musical line might surprise us today, it offers a level of insight into accompaniment practices in the Baroque and early Classical periods, when recitatives could be accompanied by a variety of instruments, depending on availability and performer preference.

Recitative
A type of singing that imitates the accents and inflections of natural speech. Composers often employ recitative for passages of text that involve quick dialogue and the advancement of plot, since the style allows singers to move rapidly through a large amount of text. Recitative was initially developed at the end of the 16th century in Italy (when it was called “monody”) and was a crucial component of the very first operas. Recitative may be accompanied by a single instrument (such as a harpsichord), a small ensemble, or the whole orchestra. The term is derived from an Italian verb meaning “to recite.”

Text Painting
A compositional technique in which music imitates the literal meaning of a text. For instance, if a text references going up, the melody might rise; if a text references a loud noise, the music might suddenly get very loud. A good example is Jack and Jill, who went up a hill (on a rising melody) to fetch a pail of water. But when they come tumbling back down the hill, the melody descends with them. Text painting can affect both the vocal line and the instrumental accompaniment.

Timbre
A French word that means “sound color,” timbre (pronounced TAM-ber) refers to the complex combination of acoustic characteristics that give each instrument or voice its unique sound. Just as we can recognize each other by the differences in our speaking voices, operatic singing voices are distinguishable by their unique timbres. Listeners can also identify orchestral instruments by their timbre without being able to see them. The creative combination of different instrumental timbres is one of the artistic aspects of orchestration.

Tremolo
An effect in the strings produced by playing the bow rapidly back and forth on a single note. The result is a trembling sound that is often used to evoke anxiety or fear. For example, Cherubini makes extensive use of tremolo strings when Medea first enters, and again in her Act III aria right before she screams, “No, dear children, no!”