from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A word or name that is used secretly to refer to another; a code name or code word.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A secret name, a code name.
from the GNU version of the Collaborative International Dictionary of English
- n. A secret name; a name by which a person is known only to the initiated.
from The Century Dictionary and Cyclopedia
- n. A private, secret, or hidden name; a name which one bears in some society or brotherhood.
crypto- + -onym (Wiktionary)