Prose is a form of written or spoken language that typically exhibits a natural flow of speech and grammatical structure. A related narrative device is the stream of consciousness, which also flows naturally but is not concerned with syntax. 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. It differs from most traditional poetry, where the form has a regular structure, consisting of verse based on metre and rhyme. However, 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."