Words related to -ian
1670s, "one who believes in the coming of the (Christian) millennium" (by 1550s in Latin plural form millenarii), from Latin millenarius "containing a thousand," from millenia "a thousand each," from mille "thousand" (see million). With -ian. As an adjective, "pertaining to the (Christian) millennium," from 1630s.
The apparent inconsistency in spelling (-n-, -nn-) results from the fact that millenarian, like millenary, does not contain the stem of the Latin annus year, which is present in millennium .... [Fowler]
1738 (adj.) "pertaining to Mongols;" 1839 (n.) "the language of the Mongols," 1846 "a native of Mongolia;" from Mongol + -ian. As a racial classification for Asiatic peoples (including Chinese, Japanese, Turks, Vietnamese, Lapps, Eskimos, etc.) "belonging to the yellow-skinned straight-haired type of mankind" [OED] in J.F. Blumenbach's system, it is attested in English by 1825 in translations of his works.
1650s, "pertaining to the god Neptune;" 1794 in the geological sense, referring to certain features (later confirmed as volcanic) believed to be formed or deposited by actions of water, from Neptune + -ian. Usually opposed in the latter sense to volcanic or plutonic. "A most violent discussion in regard to this subject was carried on, during the latter third of the eighteenth century, by geologists and theologians" [Century Dictionary]. As a noun meaning "inhabitant of the planet Neptune" it is recorded from 1870.
c. 1600 (n.) "a native of Norway," and (adj.) "of or pertaining to Norway," sometimes in early use Norvegian, from Medieval Latin Norvegia "Norway," from Old Norse Norvegr (see Norway) + -ian. Earlier words included Noreine and Norreis (both c. 1300), from Norrene (n.) "Norway" (c. 1200; the surname Norne is from late 12c.); Noregan (late 14c., from Medieval Latin); Norenish (c. 1200, adj. and n.), from late Old English Norren, from Old Norse Norrœnn.
"of or belonging to Olympus," the mountain in Thessaly fabled to be the seat of the gods, c. 1600; see Olympus + -ian. The noun meaning "one of the twelve greater god of ancient Greece" is attested from 1843, from Late Latin Olympianus, from Greek Olympios "pertaining to Olympus." The sense of "one who competes in the (modern) Olympic Games" is from 1976 (see Olympic).