Before Adelaide Crapsy developed her version, a cinquain had the same definition as quintain. These are both poems of five lines with varying rhyme, though most often forming the familiar 'abab' layout. Ms. Crapsy's version of a cinquain is somewhat different. While she was American, Japanese poetry was an obvious influence.
The style still contains five lines, but the syllables of each are strictly measured. The first and fifth contain two syllables apiece. Line two has four syllables, line three is allottted six, and the fourth line contains eight. This gives you a grand total of twenty-two syllables in which to express yourself. Rhyme is optional in this version.
An example of a cinquain:
Line 1: Thunder,