The Collaborative International Dictionary
Chthonian \Chtho"ni*an\, a. [Gr. ? in or under the earth, fr. ?, ?, earth.] Designating, or pertaining to, gods or spirits of the underworld; esp., relating to the underworld gods of the Greeks, whose worship is widely considered as more primitive in form than that of the Olympian gods. The characteristics of chthonian worship are propitiatory and magical rites and generalized or euphemistic names of the deities, which are supposed to have been primarily ghosts.
Syn: chthonic, lower, nether.
Douglas Harper's Etymology Dictionary
1804, from Latinized form of Greek khthonios (see chthonic) + -an.\n
Wiktionary
a. Pertaining to the underworld; being beneath the earth.
WordNet
Wikipedia
Chthonians (; from Greek: chthon, "earth") are fictional creatures in the Cthulhu Mythos. The species is the creation of English horror-fiction writer Brian Lumley and was first featured in his short story "Cement Surroundings" (1969)—though the creature never made a direct appearance. The chthonians had a more prominent role in Lumley's novel The Burrowers Beneath (1974), whose title was taken from one of the stories said to have been written by Robert Blake in Lovecraft's " The Haunter of the Dark."
Usage examples of "chthonian".
Like all the works of man, I saw, even these great structures were transient chimeras, destined to impermanence compared to the chthonian patience of the land.
Marry, I cannot remember the names of them all, but there was certes the pavonian touch, the Ledan straddle too, the chthonian ditch, the I think it was termed Ceutan flight and eke the Madrilenan interuberal.
On several occasions, it had seemed that a way out of these huge accumulations of earth matter could not be found, that the geological puzzle was insoluble, the chthonian arrangement of discord irresolvable: and then vale and drumlin created between them a new direction, a surprise, an escape, and the way took fresh heart and plunged recklessly still deeper into the encompassing upheaval.
In early times the Greek worship was most earnestly directed to that set of deities who resided at the gloomy centre of the earth, and who were called the chthonian gods.
You enter and are stunned by a conspiracy in which the sublime universe of heavenly ogives and the chthonian world of gas guzzlers are juxtaposed.