- AceThe lowest rank of underground citizen. Aces are peasants. They have little power in their sphere, and they are often targets of ridicule by the upper ranks. (see also: offal)
- Ace Lover A pejorative term used to describe an elite underground citizen who's too friendly to the needs of aces.
- Actual Value A number representing the true rank of a citizen based on the power they have in their sphere, rather than the official number (face value) assigned to them by their sphere. In the Underground Card Game, a citizen card's perceived actual value can be used in a challenge(...)
- ArmbandAn East Sphere citizen, named for the black armbands worn as a sphere identifier.
- BirdA South Sphere citizen, named for the band worn around the middle finger as a sphere identifier.
- Blocker See: poison blocker
- Blue-TieA North Sphere citizen, named for the blue tie worn as a sphere identifier.
- D&P Shorthand for Drugs and Poisons, the most valued industry in the North Sphere.
- Dog A West Sphere slave whose responsibilities may include domestic services, security services, or entertainment services but always include sexual services.
- Face CardAn underground citizen who holds the card rank of jack, queen, or king.
- Face Value The official rank of an underground citizen as noted on their ID, which doubles as a playing card in the Underground Card Game.
- King's Vow An agreement shared between two underground Kings, where each King offers his life as collateral. Breaking one's end of the bargain gives the other King's entire sphere license to take the offending King's life.
- Law of Touch An underground rule dictating that only citizens within two ranks of a King, Queen, or right hand (card ranks 13 and 12) may touch the King, Queen, or right hand without permission. If someone breaks the law of touch, the King, Queen, or right hand in question may dispense any punishment(...)
- NSTech A North Sphere government-owned company that manufactures drugs, pharmaceuticals, poisons, and healthcare products exclusively for the North. (see also: D&P)
- OffalA North Sphere slang term used by the upper class to denigrate aces, particularly those who ended up in the military.
- Poison Blocker An injectable medication used to block the effects of a specific poison shortly before the poisoning occurs.
- Red-SashA West Sphere citizen, named for the red sash worn as a sphere identifier.
- Sphere IdentifierAn item of clothing worn by each citizen of the underground to denote their sphere citizenship. Each sphere has its own required sphere identifier. Citizens are required to wear a sphere identifier at all times, except when naked, in their own homes, or in someone else's home with permission(...)
- Sub- A prefix used to designate an underground street or region that aligns with an above-ground Chicago street or region sharing the same name.
- SYK-21 A wide-range knock-out poison created for the North Sphere military.
- Touch Permission Authorization given by a King, Queen, or right hand to a lower ranking citizen, allowing the lower-ranking citizen to touch them even if they are not within the two ranks required by the Law of Touch.
- Underground Card Game A hierarchy-themed game played by underground citizens in which every citizen in the underground is represented on a standard playing card to reflect their rank and sphere. [Diamonds: South][Clubs: East][Hearts: West][Spades: North] Players can build their 52-card deck using any citizen(...)