You can use the word knob for any bump or bulge, like the egg-shaped knob on your head after you bumped it on the door knob.

Along the same likes as a bulging lump or protuberance, a knob is also a handle that juts out and is round shaped. The knobs on your dresser might be glass or porcelain, while the knobs on your kitchen cabinets could be made of chrome. There are also the knobs, or controls, on your old fashioned TV or radio, and the knob that's basically a lump or hunk, like a knob of butter.

Definitions of knob
  1. noun
    a circular rounded projection or protuberance
    synonyms: boss
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    a small knob
    flattened boss on the end of nail opposite to the point
    type of:
    any structure that branches out from a central support
  2. noun
    a round handle
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    doorhandle, doorknob
    a knob used to release the catch when opening a door (often called `doorhandle' in Great Britain)
    (music) a knob on an organ that is pulled to change the sound quality from the organ pipes
    type of:
    grip, handgrip, handle, hold
    the appendage to an object that is designed to be held in order to use or move it
  3. noun
    an ornament in the shape of a ball on the hilt of a sword or dagger
    synonyms: pommel
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    type of:
    decoration, ornament, ornamentation
    something used to beautify
  4. noun
    any thickened enlargement
    synonyms: node, thickening
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    type of:
    convex shape, convexity
    a shape that curves or bulges outward
Word Family