biscuit: [14] Biscuit means literally ‘twicecooked’ – from the method of cooking, in which the biscuits are returned to the oven after the initial period of baking in order to become dry or crisp. The original source of the word was probably a medieval Latin *biscoctus, from bis ‘twice’ and coctus ‘cooked’, the past participle of coquere (which is related to English cook). It reached English via Old French biscut. => cook
biscuit (n.)
respelled early 19c. from bisket (16c.), ultimately (besquite, early 14c.) from Old French bescuit (12c.), literally "twice cooked;" altered under influence of cognate Old Italian biscotto, both from Medieval Latin biscoctum, from Latin (panis) bis coctus "(bread) twice-baked;" see bis- + cook (v.). U.S. sense of "soft bun" is recorded from 1818.