A poem of 14 lines is known as a "sonnet." The sonnet is a popular form of poetry that has been used for centuries. It typically consists of 14 lines and follows a specific rhyme scheme and meter. The most common form of sonnet is the "Shakespearean" sonnet, which is divided into three quatrains (four-line stanzas) and a final couplet (two-line stanza). The rhyme scheme for a Shakespearean sonnet is ABAB CDCD EFEF GG. The sonnet is a versatile form of poetry that has been used to express a wide range of themes and emotions, from love and romance to social commentary and political satire.