lim·er·ick 
(lĭmər-ĭk)
(lĭmər-ĭk)n.
A light humorous, nonsensical, or bawdy verse of five usually anapestic lines with the rhyme scheme aabba, in which the first, second, and fifth lines are in trimeter, and the third and fourth lines are in dimeter.
[After Limerick.]