What is Paper ?
Paper is (noun) 1. a thin piece of material which you write on, and which is used for wrapping or to make books, newspapers and magazines He got a letter written on pink paper. I need another piece of paper or sheet of paper to finish my letter. There was a box of paper handkerchiefs by the bed. (NOTE: no plural for this meaning: some paper, a piece of paper, a sheet of paper) 2. a newspaper I buy the paper to read on the train every morning. My photo was on the front page of today’s paper. Our local paper comes out on Fridays. The Sunday papers are so big that it takes me all day to read them. (NOTE: The plural is papers.) 3. on paper in theory On paper the system is ideal, but no one has ever seen it working. 4. an exam The English paper was very difficult. (NOTE: The plural is papers.) 5. a piece of writing on a specific subject He wrote a paper on economics which was published in one of the learned journals. She wrote a good history paper. Synonym essay (NOTE: The plural is papers.) (verb) to cover the walls of a room with wallpaper They papered the room in a pattern of red and blue flowers.
source: Easier English, Student Dictionary Upper Intermediate Level