A fourteenth century Italian origin, the Ottava Rima is an eight-line stanza with an a-b-a-b-a-b-c-c rhyme scheme. Frances stillman in The Poets Manual and Rhyming Dictonary cites Byrons Don Juan as the best known example in the English Language.
I have written my example of the format, and show it below:
Words rip from lips hot with rage
like swarthe on a lathe streams from the tool
furled steel with a razor sharp edge
furiously writhing in a twisted spool
serving no purpose, conspicuous wastage
handled only when the heat cools.
A neighbour disputing a boundary -
enough energy to fuel a foundry.