Core tools — tool is made from the parent block of material.
Flake tools — tool is made from the a flake removed from a core; — the length is typically less than 2 times the width (L<2W)
Unifacial — flakes removed from one side of the parent core or flake
Bifacial — flakes removed from two or more faces of the parent core or flake (e.g., projectile point)Blade — the length is typically greater than 2 times the width (L>2W) and it has parallel edges.
For the production stages of a bifacial artifact see Illustration from Conlee Blackboard Lecture Notes
Heritage of Japan 