AKA is most commonly used to stand for "also known as." It can be used to refer to people, locations or anything else that uses more than one name. Example: William Henry McCarty, Jr., AKA Billy the Kid, was born in 1859.
This abbreviation is correctly written as either "AKA" (uppercase, no punctuation) or "a.k.a." (lowercase, with periods). According to the Random House Dictionary, this meaning for AKA came into use between 1945 and 1950.
AKA can also refer to the Alpha Kappa Alpha sorority. AKA is the oldest Greek letter organization for African-American women, established in 1908 at Howard University in Washington D.C. The organization is still active today.