A limerick is a five-line poem, almost always humorous, and frequently rude. Its rhyme scheme is aabba
, with the first, second and last lines having three stresses and the third and fourth lines having two. Edward Lear, a frequent writer of limericks, often had his first and last lines identical, or nearly so, making it a circular form; contemporary limericks seem to prefer to let the poem continue, as Michael Rosen's '3 Limericks' show.
Limericks do not, as a rule, lend themselves to serious poems.