whelm

From Middle English whelmen (“to turn over, capsize; to invert, turn upside down”), perhaps from Old English hwealmnian, a variant of hwealfnian, from hwealf (“arched, concave, vaulted; an arched or vaulted ceiling”), from Proto-West Germanic hwalb, from Proto-Germanic hwalbą (“arch, vault”), from Proto-Indo-European *kʷelp- (“to curve”). Cognates The English word is cognate with Dutch welven (“to arch”), Old Saxon bihwelvian (“to cover, hide”), German wölben (“to bend, curve, arch”), Icelandic hvelfa (“to overturn”), German Walm (“a vaulted roof”), Icelandic hvolf (“vaulted ceiling”), Ancient Greek κόλπος (kólpos, “bosom, hollow, gulf”). The noun is derived from the verb.