top dead center

top dead center

[¦täp ′ded ′sen·tər] (mechanical engineering) The dead-center position of an engine piston and its crankshaft arm when at the top or outer end of its stroke.

top dead center (TDC)

Topographical mapThe position of the piston within the cylinder when the piston has reached its farthest uppermost (closest to the cylinder head and valves) position.