A piece of prepared, sharp-edged stone, often flint, at least twice as long as it is wide; a long flake of ground-edge stone or knapped vitreous stone.
The four large shell plates on the sides, and the five large ones of the middle, of the carapace of the sea turtle, which yield the best tortoise shell.
An exterior product of vectors. (The product may have more than two factors. Also, a scalar counts as a 0-blade, a vector as a 1-blade; an exterior product of k vectors may be called a k-blade.)