You searched for: “pen name
nom de plume, pen name, pseudonym
nom de plume (nahm" duh PLOOM) (noun)
A term that applies to authors who do not use their real names: Mark Twain is the nom de plume for the writer Samuel Langhorne Clemens who wrote stories about boys living on the Mississippi River.
pen name (PEN naym") (noun)
The name an author assumes which is not his or her real name: Some women writers in the 1800s used a masculine pen name instead of their own names.
pseudonym (SOOD n im") (noun)
A false or fictitious name: The famous highwayman used a pseudonym so he would not be recognized when he was talking with people at the inn.

The elegant and noble chevalier wrote critical essays under his nom de plume. He thought it was safer to write under a foreign sounding pen name than to attempt to write under a readily recognizable pseudonym.