The Canzonetta or Canzonet and Canzonetta Prime are variations of the Canzone with a more definitive frame. It is a 16th century Italian secular composition often with pastoral, irreverent, or erotic themes.
The Canzonetta or Canzonet is:
• at least 2 octaves, made up of 2 quatrains of alternating rhyme.
• written with no fixed meter or line length.
• composed with a refrain, repeated in L8 of each octave.
• rhymed, ababcdcD, efefgdgD.
• is called a Canzonetta Prime when the rhyme scheme is ababcbcB dbdbebeB. In this rhyme scheme there is often a repeated rhyme word to strengthen the repetition, but it is not required.
Pasted from http://www.poetrymagnumopus.com/index.php?showtopic=1159
My thanks to Judi Van Gorder for years of work on this fine PMO resource.