The main meter of all sonnet poems in English poetry is an iambic parameter. There have been a few tetrameters and even hexameter sonnets as well. The term “sonnet” is derived from the Occitan word sonnet and Italian poetry. Occitan sonnets are distinguished by a rhyming scheme of a/bab, c/dc/dc/d.
These sonnets first appeared in Italy. The format is named after the now mostly extinct Occitan dialect of the Languedoc region in Medieval Southern France, which is probably from where the form comesfrom. The Occitan sonnet is a very traditional form.