Cinquain poems follow the following rules -

Line 1 - One word (a noun) naming the subject of the verse.
Line 2 - Two words (adjectives) describing the subject.
Line 3 - Three words (verbs) describing the subject's actions.
Line 4 - Four words giving the writer's opinion of the subject.
Line 5 - One word (noun) giving another name for the subject.

The Cinquain by Beverley George
Example by C.Alfonzetti:

Violin
Brown, shapely
Singing, shrieking, sobbing
A moody music maker
Fiddle

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