A name assigned to conceal the identity or existence of something or someone.
To assign a code name to.
A name applied to a person, project, etc. that is being kept secret or that is otherwise unidentified.
“Manhattan Project” was the code name for the secret project to develop the atomic bomb.
An internal name given to a product under development. For example, Chicago was the code name for Windows 95; Merced was the code name for Intel's Itanium chip.