Curb

n.
  1. That which curbs, restrains, or subdues; a check or hindrance; esp., a chain or strap attached to the upper part of the branches of a bit, and capable of being drawn tightly against the lower jaw of the horse.
  2. (Arch.) An assemblage of three or more pieces of timber, or a metal member, forming a frame around an opening, and serving to maintain the integrity of that opening; also, a ring of stone serving a similar purpose, as at the eye of a dome.
  3. A frame or wall round the mouth of a well; also, a frame within a well to prevent the earth caving in.
  4. A curbstone.
  5. (Far.) A swelling on the back part of the hind leg of a horse, just behind the lowest part of the hock joint, generally causing lameness.
    6. Curb bit ,
    a stiff bit having branches by which a leverage is obtained upon the jaws of horse.
    Curb pins (Horology),
    the pins on the regulator which restrain the hairspring.
    Curb plate (Arch.),
    a plate serving the purpose of a curb.
    Deck curb .
    See under Deck.