The Collaborative International Dictionary of English v.0.48:

Burghbrech \Burgh"brech`\, n. [Burgh + F. br[`e]che, equiv. to
   E. breach.] (AS. Law)
   The offense of violating the pledge given by every inhabitant
   of a tithing to keep the peace; breach of the peace.
   --Burrill.
   [1913 Webster]