cavesson

from The Collaborative International Dictionary of English v.0.48

Cavesson \Cav"es*son\, Cavezon \Cav"e*zon\, n. [F. cave[,c]on,
   augm. fr. LL. capitium a head covering hood, fr. L. caput
   head. Cf. {Caberzon}.] (Man.)
   A kind of noseband used in breaking and training horses.
   [Written also {caveson}, {causson}.] --White.
   [1913 Webster]