A position in the four-stroke combustion process wherein the piston is at the topmost point in its stroke. This can either be during the compression phase or the combustion phase
The point at the end of each stroke of a moving crank and connecting rod at which the two lie in the same straight line and the turning force applied by the connecting rod is zero. Also called dead point
(Otomotiv) The point at which the piston has reached the top of its stroke and has compressed the fuel/air mixture to the greatest extent. BTDC and ATCD mean before and after top dead center. These terms are used to refer to timing marks