Hvern

As defined by the Cleasby & Vigfusson Old Norse to English dictionary:

hvern

or hvörn, f. [proncd. kvörn or kvern, but distinction is to be made between kvern, mola, and hvern, cerebrum; for in the latter word h is the true initial, as is shewn by comparison with Ulf. hwairnei = κρανίον, Mark xv. 22; Scot. harns; Germ. hirn; Swed. hjerna; Dan. hjerne, which stand in the same relation to hvern as hjól to hvel]:—the two boat-formed white bones embedded in a fish’s brains. These bones, as well as shells, are in Icel. collected and used by children in the game of guessing, as nuts etc. are in England; hann lauk þá upp höfuðskeljum mannanna, og tók hnefa-fylli úr hverju höfði og hugði vandliga að; eintómar hvarnir, og ekki nema tvær í þorsk-kindinni, Fjölnir (1845) 52. hvarnar-skeljar, f. pl. = hvarnir.

Possible runic inscription in Younger Futhark:ᚼᚢᛁᚱᚾ
Younger Futhark runes were used from 8th to 12th centuries in Scandinavia and their overseas settlements