form of poetry with fourteen lines and strict rhyming structure
A sonnet is a poetic form which originated in the Italian poetry composed at the Court of the Holy Roman Emperor Frederick II in Palermo, Sicily. The 13th-century poet and notary Giacomo da Lentini is credited with the sonnet's invention for expressing courtly love. The Sicilian School of poets who surrounded him at the Emperor's Court are credited with its spread. The earliest sonnets, however, no longer survive in the original Sicilian language, but only after being translated into Tuscan dialect.
The term sonnet is derived from the Italian word sonetto (lit. "little song", derived from the Latin word sonus, meaning a sound). By the 13th century it signified a poem of fourteen lines that follows a very strict rhyme scheme and structure.
According to Christopher Blum, during the Renaissance, the sonnet was the "choice mode of expressing romantic love." As the sonnet form has spread to languages other than Italian, however, conventions have changed considerably and any subject is now considered acceptable for writers of sonnets, who are sometimes called "sonneteers," although the term can be used derisively.
Read more or edit on Wikipedia