Skull
Middle English scolle ; of unknown origin; compare with Old Norse skoltr .
wiktionary
From Middle English sculle, scolle (also schulle, scholle), probably from Old Norse skalli(“bald head, skull”), itself probably related to Old English sċealu(“husk”). Compare Swedish skalle, Norwegian skalle. [1]
Alternatively, perhaps from Old Norse skoltr, skolptr(“muzzle, snout”), akin to Icelandic skoltur(“jaw”), dialectal Swedish skult, skulle(“dome, crown of the head, skull”), Middle Dutch scolle, scholle, Middle Low German scholle, schulle(“clod, sod”). Compare also Old High German sciula, skiula(“skull”).
See school(“a multitude”).
etymonline
skull (n.)
"bony framework of the head," c. 1200, probably from Old Norse skalli "a bald head, skull," a general Scandinavian word (compare Swedish skulle, Norwegian skult), probably related to Old English scealu "husk" (see shell (n.)). But early prominence in southwestern texts suggests rather origin from a Dutch or Low German cognate (such as Dutch schol "turf, piece of ice," but the sense of "head bone framework" is wanting). Derivation from Old French escuelle seems unlikely on grounds of sound and sense. Old English words for skull include heafod-bolla.
