From the Italian word cavatinetta, meaning a short melodic air. The term has two meanings a short aria in repeats, these arias are mostly found in Rossini operas, he stipulated that the first statement should be sung as written and the second could be embellished at the singer's discretion. The second part is a two-part 19th century Italian aria typically found in Bellini, Donizetti and early Verdi, these are fast tempo and are designed to show off the singer's virtuosity. The slow/fast structure of a full aria was occasionally reversed, Donizetti was a master of the slow cabaletta.
Usually in bel canto operas, this is a fast aria that generally follows a more solemn, thoughtful one. It stresses the singer's vocal abilities and often ends with a high note that the singer sustains.