Etymology
From Middle English besague, besagu, besagew, from Old French besague, whence also English besagew (“rondel, armor protecting the armpit”), related to Latin bisacuta (Italian bisacuto (“double-edged”)) and besogium. Applied, in the Middle Ages, to a variety of medieval weapons or tools with two blades, edges, or faces, especially a double-bladed axe or war-hammer, but also to iron-headed cornuted staffs, clubs, or maces, spades, hoes, mattocks, and even knives.