Plain text, also known as 'clear text' or 'unformatted text, ' is a type of data consisting of only letters, numbers, and symbols. It is not formatted in any way, meaning it does not contain any special characters, fonts, or formatting. Plain text is often used for storing and transmitting data in a variety of applications, such as email, word processing, and web pages. PROSE is an acronym for Plain Representation Of Structured Entities, which is a method of representing structured data in plain text.