A condition in which gravity appears to be absent. Zero gravity occurs when gravitational forces are balanced by the acceleration of a body in orbit or free fall.
See weightlessness and microgravity.
A physical state existing in space or at a time in flight when the centrifugal thrust of a parabolic glide or turn exactly counteracts the force of gravity. ... (05 Mar 2000) ... 
Type: Term Pronunciation: zē′rō grav′i-tē Definitions: 1. A physical state existing in space or at a time in flight when the centrifugal thrust of a parabolic glide or turn exactly counteracts the force of gravity.
the condition in which the apparent effect of gravity is zero, as in the case of a body in free fall or in orbit.