[译] 地球使每一粒子或物体保留于地球表面的吸引力称为地心引力。
[误] The attraction that the earth has for every particle or body on its surface is called gravitation.

[正] The attraction that the earth has for every particle or body on its surface is called gravity.
[注] gravitation和gravity作“引力”解时常被混用,其实,gravitation指“万有引力”。如:Gravitation should be reserved for the general force throughout the universe.宇宙总引力称为万有引力。gravity指“地心引力”,如:Gravity makes water flow downhill. 地心引力使水向下流动。