A fixed form of lyric poetry that consists of fourteen lines, usually written in iambic pentameter. There are two basic types of sonnets, the Italian and the English. The Italian sonnet, also known as the Petrarchan sonnet, is divided into an octave, which typically rhymes abbaabba, and a sestet, which may have varying rhyme schemes. Common rhyme patterns in the sestet are cdecde, cdcdcd, and cdccdc. Very often the octave presents a situation, attitude, or problem that the sestet comments upon or resolves, as in John Keats's "On First Looking into Chapman's Homer." The English sonnet, also known as the Shakespearean sonnet, is organised into three quatrains and a couplet, which typically rhyme abab cdcd efef gg. This rhyme scheme is more suited to English poetry because English has fewer rhyming words than Italian. English sonnets, because of their four-part organization, also have more flexibility with respect to where thematic breaks can occur. Frequently, however, the most pronounced break or turn comes with the concluding couplet, as in Shakespeare's "Shall I compare thee to a summer's day?" See also couplet, iambic pentameter, line, octave, quatrain, sestet.