AKA is an initialism for Also Known As. An example would be Superman AKA Clark Kent.
It is usually used to either reveal the real name of a person known to the public by a pseudonym (e.g. many artists are known by their pseudonyms) or to show alternative names a person has used (some authors choose to publish by different names when targeting different audiences).
English ska band The Specials worked under the name of Special A.K.A. for some of their career.
Prior to the invention of the term "Aka", the word "or" might have been used as in "Superman OR Clark Kent". The word "or" has the disadvantage that it might be interpreted as meaning two different people, rather than one person with two identities.
