pen name

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A pseudonym used by a writer.

from The Century Dictionary.

• noun A name assumed by an author for the ostensible purpose of concealing his identity; a nom de plume; a literary pseudonym.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A fictitious name used by an author in place of their actual name.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun an author's pseudonym