Acronym standing for Alien Life Form.
ALF was also the name of an American television program broadcast between 1986 and 1990 on the NBC network. The series follows the comic mishaps of a wisecracking alien from the planet Melmak who crashlands into an Earth family's garage in Los Angeles and goes on to become a member of the family.
ALF was so named by Willy Tanner, father of the Tanner family. His actual name back on Melmak was Gordon Shumway. Melmakians are short, furry and have large noses. Cats are a common foodstuff on their planet. On a side note, ALF mentions in one episode that Melmakians have nine major organs, seven of which are stomachs.
Unsure what to do, the Tanners take ALF into their home and hide him from NASA, the Military, and their nosy neighbors until he can repair his spacecraft. It became known that Melmak had exploded, so ALF was without a home. He became a permanent member of the family.
AlfTales, an animated series, set on ALF's home planet of Melmak, ran on Saturday daytime in 1988.