What is the X in X-mas?
also aka, initialism for also known as; attested in legal documents from at least 1936.
An abbreviation meaning “also known as.” It is primarily used by law enforcement officials to specify an alias: “John Smith, aka Jonathan Jones.”
Note: The abbreviation, which also appears as AKA and a.k.a., is often used figuratively and facetiously: “my cousin, aka the worst gossip in the neighborhood.”
Also known as; alias: He's an asshole, aka a big deal