A poem of 14 lines is known as a "sonnet".
A sonnet is a type of poem that originated in Italy in the 13th century and became popular in England in the 16th century. It consists of 14 lines and typically follows a strict rhyme scheme and a specific structure.
The most common type of sonnet is the "Shakespearean" or "English" sonnet, which is composed of three quatrains (four-line stanzas) and a final couplet (two-line stanza). The rhyme scheme of a Shakespearean sonnet is usually ABAB CDCD EFEF GG, meaning that the first and third lines of each quatrain rhyme with each other, as do the second and fourth lines, and the final couplet rhymes with each other.
Sonnet form is often used to express intense or complex emotions, such as love, loss, and mortality. Many of the greatest poets in history have written sonnets, including William Shakespeare, John Donne, Elizabeth Barrett Browning, and Pablo Neruda.