Madrigal is originally a pastoral song. It is a short lyric, especially one to be set to music and intended for several voices.
It arose in northern Italy in the 14th c. and Petrarch wrote a number of them. In the 16th c. there was a revival of the form and it became extremely popular in England in Tudor times.
Metrically it showed much variety. In the 14th c. it tended to consist of two or three tercets followed by one or two rhyming couplets. By the 16th c. there were few rules, but for the most part, madrigals were of ten to fourteen lines and normally ended with a rhyming couplet.
The themes were usually love, pastoral, or satiric.
Many Tudor poets attempted it, but its three famous English composers were Thomas Morley, Thomas Weelkes, and John Wilbye.