Musical piece for a single voice as part of a larger work
In music, an aria (Italian: [ˈaːrja]; pl.: arie, Italian: [ˈaːrje]; arias in common usage; diminutive form: arietta, Italian: [aˈrjetta]; pl.: ariette; in English simply air) is a self-contained piece for one voice, with or without instrumental or orchestral accompaniment, normally part of a larger work. The typical context for arias is opera, but vocal arias also feature in oratorios and cantatas, or they can be stand-alone concert arias. The term was originally used to refer to any expressive melody, usually, but not always, performed by a singer. Etymology.
https://en.wikipedia.org/wiki/Aria