- "You refer to us as 'alien,' and the Princess calls us 'non-Human.' Why are we defined by you and in comparison to you?"
- ―Borsk Fey'lya
Alien was a Humanocentric biological—and sometimes political—term to describe a sentient species or a person of a species other than Humans or some near-Humans. The term may have been derived from the first impression of early Humans, when they had their first contacts with species from other planets. However, it seems to have been prevalent even in subsequent millennia.
Since Humans were the most common and prominent sentient species in galactic affairs and history, they were often considered a standard or average to which the biology, psychology, and culture of other species were compared. Thus species with a body type roughly similar to Humans were often referred to as humanoid.
Aliens were sometimes victims of speciesism, being derided and avoided by Humans in certain societies, like Taris during the blockade of the Sith. Prejudice against aliens led many aliens and planets with alien native species to join the Confederacy of Independent Systems during the Clone Wars and Alliance to Restore the Republic during the Galactic Civil War, both times hoping for freedom and safety from prejudice.
Behind the scenes
The word alien originally meant "stranger," and came from the Latin word alienus of the same meaning. The word was directly borrowed into English, and frequently used in the sense of "foreigner," as in the legal term for a person who is not a native or naturalized citizen of the land where they are found. It was also used in biology to describe plant or animal species which were not naturally found in a given part of the Earth, but had been introduced there.