hull

From Middle English hul, hulle, holle (“seed covering, hull of a ship”), from Old English hulu (“seed covering”), from Proto-Germanic *hul-, perhaps from Proto-Indo-European *ḱel- (“to cover, hide”); or possibly from Proto-Indo-European *kal- (“hard”).

Compare Dutch hul (“hood”), German Hülle (“cover, wrap”), Hülse (“hull”); also Old Irish calad, calath (“hard”), Latin callus, callum (“rough skin”), Old Church Slavonic калити (kaliti, “to cool, harden”). For the sense development, compare French coque (“nutshell; ship's hull”), Ancient Greek φάσηλος (phásēlos, “bean pod; yacht”).

From Middle English holle, hoole (“hull, hold of a ship, ship”), of uncertain origin. Possibly a variant and special use of Etymology 1 above, conformed to hull. Alternatively, a variant of Middle English hole, hoole, holle (“hiding place, lair, den, shelter, compartment”, literally “hole, hollow”), related to Middle Dutch and Dutch hol (“hole, ship's cargo hold”). More at hole.