Where does “ktooninen” come from?

ktooninen (Finnish) comes from Ancient Greek χθόνιος, from Ancient Greek -ῐος, from Proto-Indo-European -yós — Creates adjectives from noun or verb stems.

ktooninen (Finnish): chthonic

Definitions

chthonic

Ancestry of “ktooninen”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	χθόνιος	underground, subterranean, chthonian
2	Ancient Greek	-ῐος	belonging to; of”, “belonging to”, “pertaining to
3	Proto-Indo-European	-yós	Creates adjectives from noun or verb stems

Every word from Proto-Indo-European -yós →Every word from Ancient Greek -ῐος →Every word from Ancient Greek χθόνιος →