The sonnet has a fixed form of 14 lines of 10 syllables each. It is usually written in iambic pentameter—much like the rhythm of natural speech. There are two parts of a sonnet, consisting of three quatrains and an ending couplet. The sonnet explores a subject of particpular interest to the poet. The rhyme scheme is abab, cdcd, efef, gg. The summing up of the theme is expressed in the last couplet (two lines). The sonnet was invented by an Italian poet, Giacomo da Lentino in the 1200s and is one of the best-known forms in the Western World used by Shakespeare, Milton, Wordsworth and other great poets. The most popular sonnets are Italian and English, also known as Shakespearean.
Example:
Shall I compare thee to a summer’s day?
Thou art more lovely and more temperate:
Rough winds do shake the buds of May,
And summers lease hath all too short a date:
Sometimes too hot the eye of heavens shines,
And often his gold complexion dimm’d;
And every fair from fair sometime declines,
By chance or nature’s changing course untrimm’d:
But thy eternal summer shall not fade.
Nor lose possession of that fair thou ow’st;
Nor shall Death brag thou wanderest in his shade,
When in eternal lines to time thou grow’st;
So long as men can breathe or eyes can see,
So long lives this and this gives life to thee.
~Shakespeare