1. The very slight gravitational field experienced by a mass that is far removed from any other mass, as in intergalactic or interstellar space.

2. A condition, such as a free fall or orbital motion, in which acceleration of an object causes it to appear weightless even in the presence of a strong gravitational force.

3. A minute shift in the earth's gravitational field that can occur through geologic processes in a region, such as the movement of the earth's crust along fault lines.