Noun
(games) An engine-powered miniature racing car running on a circular track, tethered by cables to a central pole, popular in the 1940s.
Hypernym: tether car
(dated) A collector or enthusiast of such miniature cars.
(Can we verify this sense?) (science fiction) An anti-gravity propulsion system capable of faster-than-light travel, powered by the hypothetical Blackett effect.
Source: en.wiktionary.org