xenophobia

First recorded in 1890–95; xeno- “foreign, strange” + -phobia “fear”

Xenophobia entered English in the late 1800s. Its first element derives from the Greek word xénos , which means “stranger, guest” when used as a noun, and “alien, foreign, strange” when used as an adjective. The second element of xenophobia traces back to the Greek word phóbos , which means “fear, panic.” While the concept of xenophobia undoubtedly existed before the late 19th century, any feelings associated with xenophobia were not expressed with this particular word before that time.
More recently, the term xenophobia has been used by science-fiction writers to refer to fear or hatred of intelligent lifeforms from outer space. The term alien itself originally referred to foreigners, and only took on the extended meaning of extraterrestrial beings in the 1920s.
A related term that often comes up in the context of xenophobia is otherness : “the quality or state of being perceived or treated as different, foreign, strange, etc.” Otherness has existed in English since the 1500s, though its early uses were often in the context of a spiritual transcendence beyond the human experience. By the 1800s, otherness was used in reference to cultural foreignness.
While the etymology of xenophobia explicitly links it to the psychological response of fear, otherness can be thought of in terms of sociological identity, defining what is normative by naming what is not.