The Collaborative International Dictionary of English v.0.48:

Breaker \Break"er\, n.
   1. One who, or that which, breaks.
      [1913 Webster]

            I'll be no breaker of the law.        --Shak.
      [1913 Webster]

   2. Specifically: A machine for breaking rocks, or for
      breaking coal at the mines; also, the building in which
      such a machine is placed.
      [1913 Webster]

   3. (Naut.) A small water cask. --Totten.
      [1913 Webster]

   4. A wave breaking into foam against the shore, or against a
      sand bank, or a rock or reef near the surface.
      [1913 Webster]

            The breakers were right beneath her bows.
                                                  --Longfellow.
      [1913 Webster]

   5. a quarry worker who splits off blocks of stone.

   Syn: ledgeman.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

breaker
    n 1: a quarry worker who splits off blocks of stone [syn:
         breaker, ledgeman]
    2: waves breaking on the shore [syn: surf, breaker,
       breakers]
    3: a device that trips like a switch and opens the circuit when
       overloaded [syn: circuit breaker, breaker]