subterraneous
From LSJ
Ἐν ἀρχῇ ἦν ὁ Λόγος, καὶ ὁ Λόγος ἦν πρὸς τὸν Θεόν, καὶ Θεὸς ἦν ὁ Λόγος (Κατὰ Ἰωάννην 1:1) → In the beginning was the Word, and the Word was with God, and the Word was God.
Ἐν ἀρχῇ ἦν ὁ Λόγος, καὶ ὁ Λόγος ἦν πρὸς τὸν Θεόν, καὶ Θεὸς ἦν ὁ Λόγος (Κατὰ Ἰωάννην 1:1) → In the beginning was the Word, and the Word was with God, and the Word was God.
See subterranean.
subterraneous thunder: V. βροντήματα χθόνια, τά.