*bhreg- Look up *bhreg- at Dictionary.com
Proto-Indo-European root meaning "to break."

It forms all or part of: anfractuous; Brabant; bracken; brake (n.1) "stopping device for a wheel;" brake (n.2) "kind of fern;" brash; breach; break; breccia; breeches; brioche; chamfer; defray; diffraction; fractal; fraction; fractious; fracture; fragile; fragility; fragment; frail; frangible; infraction; infringe; irrefragable; irrefrangible; naufragous; ossifrage; refract; refraction; refrain (n.); refrangible; sassafras; saxifrage; suffragan; suffrage.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit (giri)-bhraj "breaking-forth (out of the mountains);" Latin frangere "to break (something) in pieces, shatter, fracture;" Lithuanian brasketi "crash, crack;" Old Irish braigim "break wind;" Gothic brikan, Old English brecan "to break."