The Collaborative International Dictionary of English v.0.48:

Knob \Knob\, n. [A modification of knop. Cf. Nob.]
   1. A hard protuberance; a hard swelling or rising; a bunch; a
      lump; as, a knob in the flesh, or on a bone.
      [1913 Webster]

   2. A knoblike ornament or handle; as, the knob of a lock,
      door, or drawer. --Chaucer.
      [1913 Webster]

   3. A rounded hill or mountain; as, the Pilot Knob. [U. S.]
      --Bartlett.
      [1913 Webster]

   4. (Arch.) See Knop.
      [1913 Webster]

   Knob latch, a latch which can be operated by turning a
      knob, without using a key.
      [1913 Webster]