Prose is a form of written or spoken language that follows the natural flow of speech, uses a language's ordinary grammatical structures, or follows the conventions of formal academic writing. It differs from most traditional poetry, where the form consists of verse (writing in lines) based on rhythmic metre or rhyme. The word "prose" first appears in English in the 14th century. It is derived from the Old French prose, which in turn originates in the Latin expression prosa oratio (literally, straightforward or direct speech). Works of philosophy, history, economics, etc., journalism, and most fiction (an exception is the verse novel), are examples of works written in prose. Developments in twentieth century literature, including free verse, concrete poetry, and prose poetry, have led to the idea of poetry and prose as two ends on a spectrum rather than firmly distinct from each other. The British poet T. S. Eliot noted, whereas "the distinction between verse and prose is clear, the distinction between poetry and prose is obscure."