|flegə|thänt ə l, -ejə|- adjective
or phleg·e·thon·tic -tik
Usage: usually capitalized
Etymology: Latin phlegethont is phlegethontal (from Phlegethon, principal river of Hades that ran with fire instead of water, from Greek Phlegethōn, from phlegethein to blaze, from phlegein to burn) + English -al or -ic
archaic : of, relating to, or resembling a river of fire : burning