Music glossary

Opera
A dramatic work in one or more acts, set to music for singers and instrumentalists.

Opera bouffé
A light, often satirical opera or operetta.

Opera buffa (or opera comique)
A comic opera in the 18th century.

Operetta (or Operette)
19th and early 20th century term for lighter opera. Performance includes both songs and spoken dialogue.

Organ
Keyboard instrument consisting of pipes and reeds. Today almost exclusively used in churches.

Ornaments
Also called embellishments, these are notes considered to be an extra embellishment of a melody which are either added spontaneously by the performer or indicated by the composer on the score by signs or notation.

Ossia
It.: "or". Indicates an alternative passage in a composition.

Ouverture
An orchestral piece opening an opera.