A sestain is a six-line poem or repetitive unit of a poem of this format (musaddas), comparable to quatrain which is a four-line poem or a unit of a poem. There are many types of sestain with different rhyme schemes, for example , , or. The sestain is probably next in popularity to the quatrain in European literature. Usually there are three rhymes in the six-line strophe, but sometimes there are only two.