1. Rate of change in velocity; expressed as units of length per unit of time squared or as meters per second per second (m/s2) in SI; a vector quantity. 2. gravitational accelerationThe rate of change in velocity caused by the force of gravity; approximately 9.81 m/s2 downward or 32 ft/s2 downward; also referred to as acceleration due to gravity; often abbreviated as g. 3. Change in position that occurs when all points on a body or object move in circular paths about the same fixed axis; also referred to as rotary motion or rotation. 4. Change in velocity divided by the time it took for the change to occur; expressed as units of length per unit of time squared or as meters per second per second in SI; a vector quantity. 5. Distance traveled divided by the time it took to travel that distance; expressed as units of length per unit of time or as meters per second in SI; a scalar quantity