form of language which applies ordinary grammatical structure and natural flow of speech
Prose is a form or technique of language that exhibits a natural flow of speech and grammatical structure. Novels, textbooks and newspaper articles are all examples of prose. The word prose is frequently used in opposition to traditional poetry, which is language with a regular structure with a common unit of verse based on metre and/or rhyme. However, as T. S. Eliot noted, while "the distinction between verse and prose is clear, the distinction between poetry and prose is obscure"; developments in modern literature, including free verse and prose poetry, have led to the two techniques indicating two ends on a spectrum of ways to compose language, as opposed to two discrete options.
Read more or edit on Wikipedia