A threeline stanza form borrowed from the Italian poets. The rhymescheme is aba, bcb, cdc, ded, etc. In other words one rhymesound is used for the first and third line of each stanza and a new rhyme introduced for the second line, this new rhyme, in turn, being used for the first and third lines of the subsequent stanza. Usually the meter is iambic pentameter. The opening of Shelleys Ode to the West Wind, which is written in terza rima, illustrates it.

Website: http://www.writing.upenn.edu/~afilreis/88v/terza.html