What common element do all sonnets share?

All sonnets share the defining characteristic of consisting of 14 lines. This structure is fundamental to the form of a sonnet and is what distinguishes it from other types of poetry. The use of 14 lines allows poets to explore themes of love, nature, time, and beauty in a concise manner, often utilizing specific rhyme schemes and meter, such as iambic pentameter.

While many sonnets do follow particular rhyme schemes, this is not a universal rule and varies between different types of sonnets, such as Petrarchan and Shakespearean. Additionally, the forms do not usually tell a story in a narrative sense, as the focus is often more on emotion and reflection rather than plot. Lastly, sonnets are traditionally structured, contrasting with free verse, which does not adhere to a specific line or rhyme format. Therefore, the 14-line structure is the quintessential element that unites all sonnets.