Up to the hub

Hub Hub (h[u^]b), n. [See 1st {Hob}.] 1. The central part, usually cylindrical, of a wheel; the nave. See Illust. of {Axle box}. [1913 Webster]

2. The hilt of a weapon. --Halliwell. [1913 Webster]

3. A rough protuberance or projecting obstruction; as, a hub in the road. [U.S.] See {Hubby}. [1913 Webster]

4. A goal or mark at which quoits, etc., are cast. [1913 Webster]

5. (Diesinking) A hardened, engraved steel punch for impressing a device upon a die, used in coining, etc. [1913 Webster]

6. A screw hob. See {Hob}, 3. [1913 Webster]

7. A block for scotching a wheel. [1913 Webster]

8. The central location within which activities tend to concentrate, or from which activities radiate outward; a focus of activity. [PJC]

9. Hence: (Aeronautics) A large airport used as a central transfer station for an airline, permitting economic air transportation between remote locations by directing travellers through the hub, often changing planes at the hub, and thus keeping the seat occupancy rate on the airplanes high. The hub together with the feeder lines from remote locations constitute the so-called

{hub and spoke system} of commercial air passenger transportation. A commercial airline may have more than one such hub. [PJC]

10. The city of Boston, Massachusetts referred to locally by the nickname {The Hub}. [PJC]

{Hub plank} (Highway Bridges), a horizontal guard plank along a truss at the height of a wagon-wheel hub.

{Up to the hub}, as far as possible in embarrassment or difficulty, or in business, like a wheel sunk in mire; deeply involved. [Colloq.] [1913 Webster]