type of mineral, 1800; from Greek pyr "fire" (see pyro-) + xenos "stranger" (see xeno-). According to OED, so named in 1796 by Abbé Haüy, French mineralogist, "because he thought it 'a stranger in the domain of fire' or alien to igneous rocks." Related: Pyroxenic.

"prevention of aliens from settling in Sparta," Greek, literally "expulsion of foreigners," from xenelatein "to expel foreigners," from xenos "stranger" (see xeno-) + elatos, verbal adjective of elaunein "drive, drive away, beat out."

"fertilization by pollen from a different plant," 1877, from xeno- "strange, foreign" + -gamy "fertilization." Related: Xenogamous.

1894, from xeno- "foreign, strange" + -lith "stone."

1922, from xeno- "foreign, strange" + -phile.

1897, from xeno- "foreign, strange" + -phobe. As an adjective from 1908.

"fear or hatred of strangers or what is foreign," 1880, London Daily News, April 12, in which it is coupled with xenomania, in reference to English attitudes toward the French:

Here, however, as in other cases, we are inclined to think that intelligent xenomania is decidedly preferable to the Xenophobia which is of necessity and always unintelligent.

See xeno- "foreign, strange" + -phobia "fear." It was infrequent in 1890s publications but more common from 1903, influenced by or from French xénophobie (by 1901), xénophobe. Earlier (c. 1884) it meant what is now meant by agoraphobia.

Proto-Indo-European root meaning "stranger, guest, host," properly "someone with whom one has reciprocal duties of hospitality," representing "a mutual exchange relationship highly important to ancient Indo-European society" [Watkins]. But as strangers are potential enemies as well as guests, the word has a forked path.

The word ghos-ti- was thus the central expression of the guest-host relationship, a mutual exchange relationship highly important to ancient Indo-European society. A guest-friendship was a bond of trust between two people that was accompanied by ritualized gift-giving and created an obligation of mutual hospitality and friendship that, once established, could continue in perpetuity and be renewed years later by the same parties or their descendants. [Calvert Watkins, "American Heritage Dictionary of Indo-European Roots"]

It forms all or part of: Euxine; guest; hospice; hospitable; hospital; hospitality; hospodar; host (n.1) "person who receives guests;" host (n.2) "multitude;" hostage; hostel; hostile; hostility; hostler; hotel; Xenia; xeno-; xenon.

It is the hypothetical source of/evidence for its existence is provided by: Greek xenos "guest, host, stranger;" Latin hostis, in earlier use "a stranger," in classical use "an enemy," hospes "host;" Old Church Slavonic gosti "guest, friend," gospodi "lord, master;" Old English gæst, "chance comer, a stranger."