n (chiefly|North America) A small bread usually made with baking soda, similar in texture to a scone, but usually not sweet.
n (context|nautical) The "bread" formerly supplied to naval ships; made with very little water, kneaded into flat cakes and slowly baked; often infested with weevils.
n (context|woodworking) An thin oval wafer of wood or other material inserted into mating slots on pieces of material to be joined to provide gluing surface and strength in shear.