Monday word: chthonic

[ersatz-read.livejournal.com]

chthonic (thŏn′ĭk), adj.
Of or relating to the underworld.

Note the pronunciation: the 'ch' is silent.

Etymology:  from Greek khthonios, of the earth

Persephone is a a vegetation goddess as well as a chthonic goddess.
I believe this word was on my mind because I just put santa-thulhu (with his Adipose sidekick) on display for the season.