n.
the furthest point of a piston's travel, at which it changes from an upward to a downward ... the figure shows the piston at top dead centre
Oxford Dictionary
n.
the exact center of something: Kansas, the dead center of the USA most notebooks have a logo sitting dead center
Oxford American Dictionary
ph.
the arid interior of Australia
Oxford Dictionary
n.
the furthest point of a piston's travel, at which it changes from an upward to a downward ... the figure shows the piston at top dead center
Oxford American Dictionary