Limerick (poetry)

A limerick is a funny, silly, rude, or sexual poem that has five (or four) lines. Lines 1, 2, and 5 rhyme with each other and have eight (or more) syllables. Lines 3 and 4 have a different rhyme word and have five (or more) syllables each. The poem often begins with "There was a ...", but it doesn't have to.
This one is by Rudyard Kipling:
A limerick by Edward Lear, who is famous for writing this kind of poem, has four lines because he combines lines 3 and 4 into one ten-syllable line: