Poetry (from the Latin poeta, a poet) is a form of literary art in which language is used for its aesthetic and evocative qualities in addition to, or in lieu of, its apparent meaning. Poetry may be written independently, as discrete poems, or may occur in conjunction with other arts, as in poetic drama, hymns, lyrics, or prose poetry. It is published in dedicated magazines (the longest established being Poetry and Oxford Poetry), individual collections and wider anthologies.

Poetry, and discussions of it, have a long history. Early attempts to define poetry, such as Aristotle's Poetics, focused on the uses of speech in rhetoric, drama, song, and comedy. Later attempts concentrated on features such as repetition, verse form and rhyme, and emphasized the aesthetics which distinguish poetry from more objectively informative, prosaic forms of writing, such as manifestos, biographies, essays, and novels . From the mid-20th century, poetry has sometimes been more loosely defined as a fundamental creative act using language.

Poetry often uses particular forms and conventions to suggest alternative meanings in the words, or to evoke emotional or sensual responses. Devices such as assonance, alliteration, onomatopoeia, and rhythm are sometimes used to achieve musical or incantatory effects. The use of ambiguity, symbolism, irony, and other stylistic elements of poetic diction often leaves a poem open to multiple interpretations. Similarly, metaphor, simile, and metonymy create a resonance between otherwise disparate images—a layering of meanings, forming connections previously not perceived. Kindred forms of resonance may exist, between individual verses, in their patterns of rhyme or rhythm.

Some forms of poetry are specific to particular cultures and genres, responding to the characteristics of the language in which the poet writes. While readers accustomed to identifying poetry with Dante, Goethe, Mickiewicz and Rumi may think of it as being written in lines based upon rhyme and regular meter, there are traditions, such as Biblical poetry, that use other approaches to achieve rhythm and euphony. Much of modern British and American poetry is to some extent a critique of poetic tradition, playing with and testing (among other things) the principle of euphony itself, to the extent that sometimes it deliberately does not rhyme or keep to set rhythms at all. In today's globalized world poets often borrow styles, techniques and forms from diverse cultures and languages.

Poetry as an art form may predate literacy. Many ancient works, from the Indian Vedas (1700–1200 BC) and Zoroaster's Gathas (1200-900 BC) to the Odyssey (800–675 BC), appear to have been composed in poetic form to aid memorization and oral transmission, in prehistoric and ancient societies. Poetry appears among the earliest records of most literate cultures, with poetic fragments found on early monoliths, runestones, and stelae.

The oldest surviving epic poem is the Epic of Gilgamesh, from the 3rd millennium BC in Sumer (in Mesopotamia, now Iraq), which was written in cuneiform script on clay tablets and, later, papyrus. Other ancient epic poetry includes the Greek epics Iliad and Odyssey, the Old Iranian books the Gathic Avesta and Yasna, the Roman national epic, Virgil's Aeneid, and the Indian epics Ramayana and Mahabharata.

The efforts of ancient thinkers to determine what makes poetry distinctive as a form, and what distinguishes good poetry from bad, resulted in "poetics"—the study of the aesthetics of poetry. Some ancient societies, such as the Chinese through the Shi Jing, one of the Five Classics of Confucianism, developed canons of poetic works that had ritual as well as aesthetic importance. More recently, thinkers have struggled to find a definition that could encompass formal differences as great as those between Chaucer's Canterbury Tales and Matsuo Bashō's Oku no Hosomichi, as well as differences in context spanning Tanakh religious poetry, love poetry, and rap.

Context can be critical to poetics and to the development of poetic genres and forms. Poetry that records historic events in epics, such as Gilgamesh or Ferdowsi's Shahnameh, will necessarily be lengthy and narrative, while poetry used for liturgical purposes (hymns, psalms, suras, and hadiths) is likely to have an inspirational tone, whereas elegy and tragedy are meant to evoke deep emotional responses. Other contexts include Gregorian chants, formal or diplomatic speech, political rhetoric and invective, light-hearted nursery and nonsense rhymes, and even medical texts.

The Polish historian of aesthetics, Władysław Tatarkiewicz, in a paper on "The Concept of Poetry," traces the evolution of what is in fact two concepts of poetry. Tatarkiewicz points out that the term is applied to two distinct things that, as the poet Paul Valéry observed, "at a certain point find union. Poetry [...] is an art based on language. But poetry also has a more general meaning [...] that is difficult to define because it is less determinate: poetry expresses a certain state of mind."