Xenos

Xenos (pronounced ZEE-nos) is a High Gothic term used by the people and Adepta of the Imperium of Man that means "stranger" and "alien". It is often used by the Adeptus Terra to signify enemy alien or off-world non-human forces. The main xenos races in the Milky Way Galaxy are the Tau, Necrons, Eldar, Dark Eldar, Orks and Tyranids, though there are literally countless other intelligent alien species, most of them hostile, that Mankind has encountered over the long millennia of its expansion across the stars.