Английский разговорный словарь (основной) - orbital adjective (youth culture)

In British youth slang, of a party (especially an acid-house party: see acid house): taking place beside or near the M25 London orbital motorway. Etymology: The word is taken from the official name of the M25, London orbital motorway. History and Usage: Orbital parties were a phenomenon of 1989-90, taking the place of warehouse parties in popularity among London's youth. They probably represent a passing fashion. If you've been to any of the major house parties, you'd know them by sight, if not by name. Their multiscreen projections of slides and film loops have featured in orbital parties, at the Astoria and Heaven, in Rifat Ozbek's 1988/89 fashion shows, and at Energy's recent Docklands all-dayer. The Face June 1990, p. 18