1) The most disreputable section of any hamlet, village, burg, town, county, colony, province, state, nation, planet, system or sector; 2) On any rotating ship, station or humanoid-made world, the lowest or innermost ring or level still habitable (though uncomfortably so) by sentient beings, due to its very low gravity; 3) The lowest or innermost level of a Recreation Station, usually inhabited by robots and cyberforms, low-end sex workers and rogue droids, cybernetically-enhanced humanoids and natives of low-gravity worlds, and frequented by the worst sort of gawkers, geezers, con artists, pawn-brokers, fences, felons, life-dealers, losers of every make and model, and the ubiquitous Galactic Girl Guides. Let the visitor beware!