From Certain Notes of Instruction by George Gascoigne (1575)

Then have you Sonnets: some think that all Poems (being short) may he called Sonnets, as indeed it is a diminutive word derived of Sonare, but yet I can best allow to call those Sonnets which are of fourteen lines, every line containing ten syllables. The first twelve do rhyme in staves of four lines by cross meter, and the last two rhyming together do conclude the whole. There are Dizaines, and Sixaines, which are of ten lines, and of six lines, commonly used by the French, which some English writers do also term by the name of Sonnets.