Anti-gravity
Anti-gravity refers to the state in which an object defies the laws of gravity. 

The cloud city Stratos was built, by the Ardanans, above the surface of the planet Ardana, centuries prior to 2269. The city was described by Spock as "the finest example of sustained anti-gravity elevation [he had] ever seen." ()

During the 23rd and 24th centuries, the Federation employed anti-gravs and later anti-grav sleds to assist in the moving of large or bulky items. (; , et al.) 

At the same time it was not uncommon to see anti-gravity wheelchairs in use by disabled persons. (; , et al.) Jadzia Dax, via the , had been familiar with this type of technology as early as the late 22nd century. ()

See also 
Anti-grav
Artificial gravity

External link 
 
 

ja:反重力
Physics