in fencing, denotes a blunt sword, having a button at the end covered with leather, which is used in learning the art of fencing. See Fencing.

Foil, amongst glass-grinders, a sheet of tin, with quicksilver, or the like, laid on the back of a looking-glass, to make it reflect.

Foil, amongst jewellers, a thin leaf of metal placed under a precious stone, to make it look transparent, and give it an agreeable colour, either deep or pale.