Merriam-Webster's Word of the Day for October 1, 2024 is: chthonic \THAH-nik\ adjective Chthonic means "of or relating to the [underworld](https://www.merriam-webster.com/dictionary/underworld)." It is used as a synonym of [infernal](http://www.merriam-webster.com/dictionary/infernal). // Cleo compared entering her brother's basement bedroom to a descent into chthonic regions: it was dark and odd-smelling, and she was a little frightened of what she might find there. [See the entry >](https://www.merriam-webster.com/dictionary/chthonic) Examples: "Before the backdrop of a [magmatic](https://www.merriam-webster.com/dictionary/magmatic) cavern stand three adventurers: a warrior, a mage, and a trickster who, with a roll of the dice, are preparing to defeat a tentacled chthonic beast." — Christopher Cruz, Rolling Stone, 14 May 2024 Did you know? Chthonic might seem a lofty and learned word, but it's actually pretty down-to-earth in its origin and meaning. It comes from chthōn, which means "earth" in Greek, and it is associated with things that dwell in or under the earth. It is most commonly used in discussions of mythology, particularly underworld mythology. [Hades](http://www.merriam-webster.com/dictionary/Hades) and [Persephone](http://www.merriam-webster.com/dictionary/Persephone), who reign over the underworld in Greek mythology, might be called "chthonic deities," for example. Chthonic has broader applications, too. It can be used to describe something that resembles a mythological underworld (e.g., "chthonic darkness"), and it is sometimes used to describe earthly or natural things, as opposed to those that are elevated or [celestial](http://www.merriam-webster.com/dictionary/celestial).