The Collaborative International Dictionary of English v.0.48:

Knob \Knob\, v. i.
   To grow into knobs or bunches; to become knobbed. [Obs.]
   --Drant.
   [1913 Webster]

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]

The Collaborative International Dictionary of English v.0.48:

Knop \Knop\ (n[o^]p), n. [OE. knop, knoppe; cf. D. knop, knoop,
   G. knopf, Dan. knap, knop, Sw. knapp, knopp, button, bud,
   Icel. knappr, and E. knap, n. Cf. Knap, Knob.]
   1. A knob; a bud; a bunch; a button.
      [1913 Webster]

            Four bowls made like unto almonds, with their knops
            and their flowers.                    --Ex. xxv. 21.
      [1913 Webster]

   2. (Arch.) Any boldly projecting sculptured ornament; esp.,
      the ornamental termination of a pinnacle, and then
      synonymous with finial; -- called also knob, and
      knosp.
      [1913 Webster]

   Knop sedge (Bot.), the bur reed (Sparganium); -- so
      called from its globular clusters of seed vessels.
      --Prior.
      [1913 Webster]

WordNet (r) 3.0 (2006):

knob
    n 1: a circular rounded projection or protuberance [syn: knob,
         boss]
    2: a round handle
    3: any thickened enlargement [syn: node, knob, thickening]
    4: an ornament in the shape of a ball on the hilt of a sword or
       dagger [syn: knob, pommel]

Moby Thesaurus II by Grady Ward, 1.0:

116 Moby Thesaurus words for "knob":
   anthill, ball, balloon, barrow, bilge, bladder, blain, bleb,
   blister, blob, boll, bolus, boss, bow, brae, bubble, bulb, bulbil,
   bulblet, bulge, bulla, bump, bunch, burl, butte, button, cahot,
   chine, clump, coarsen, condyle, convex, dowel, down, drumlin, dune,
   ear, ellipsoid, fell, flange, flap, foothills, gall, geoid, globe,
   globelet, globoid, globule, glomerulus, gnarl, gob, gobbet,
   granulate, handle, hill, hillock, horripilate, hummock, hump,
   hunch, jog, joggle, knoll, knot, knur, knurl, lip, loop, lump,
   mole, molehill, monticle, monticule, moor, mound, mountain, nevus,
   nub, nubbin, nubble, oblate spheroid, orb, orbit, orblet,
   papilloma, peg, pellet, pimple, projection, prolate spheroid,
   protrusion, protuberance, rib, ridge, ring, rondure, rough,
   rough up, roughen, sand dune, shoulder, sphere, spheroid, spherule,
   spine, stud, style, swell, tab, tubercle, tubercule, verruca,
   vesicle, wale, wart, welt