The Cuarteto, Spanish for quartet, is an Argentine genre of music and also a stanzaic form which is simply a quatrain made up of rhymed hendecasyllabic lines.
The Cuarteto is:
• stanzaic, a poem made up of any number of quatrains.
• syllabic, hendecasyllabic (11 syllable) lines.
• rhymed, either abab or abba rhyme scheme.
Pasted from http://www.poetrymagnumopus.com/index.php?showtopic=1433
My thanks to Judi Van Gorder for years of work on this fine PMO resource.