Definition
The exact center.
Origins
The sense referring to a piston position was originally a variant of earlier dead-point. The adjective carries two of its senses at once in this construction: both "exact" and "without force imparted". As the piston passes through dead center, there is an instant when it is neither being pushed nor being pulled.
Also Said As
- bullseye
How People Actually Use It
The act of accomplishing or doing something with the result of impressive success.
"Matt: Hey man, how'd your interview go? Dan: Took that shit 450 dead center."
Source: Urban Dictionary