Usually gravity and gravitation are used for same thin n mostly as synonyms.But literally there is vast differences between them.
- Gravitation is the force of attraction between two bodies with masses as described as Newton's first law .
- Gravity is the special case of Gravitation in which one mass is of earth or any other planet.
- Since Gravitation is applied in any galaxy,atom or body it is universal.So called universal gravitaional constant.
Fore more see here