A flake removed during the thinning or resharpening of bifaces. These flakes are relatively flat, have broad, shallow flake scars (produced by the detachment of previous thinning flakes from the dorsal face), and tend to exhibit a feathering out of lateral margins. The proximal end of the flake often retains the edge of the biface and, if the platform is retained, it often exhibits a low angle and evidence of crushing or grinding (i.e., platform preparation).