A principle, or a point in time, on which subsequent reasonings or events depend.
“This argument was the hinge on which the question turned.”
A jointed or flexible device that allows the pivoting of a door etc.
verb
The breaking off of the distal end of a knapped stone flake whose presumed course across the face of the stone core was truncated prematurely, leaving not a feathered distal end but instead the scar of a nearly perpendicular break.