A chamfron, or chanfron, is a piece of armor designed to protect a horse’s head during battle. It is affronty by default; period examples could be shown with a plumed crest attached to the top as well.
The illustration shows two forms of chamfron. The dexter chamfron is the period heraldic form, taken from the badge of the Earl of Shrewsbury, c.1513 [HCE xxix]. The sinister chamfron is based on an actual piece of horse armor, dated 1558 [Neubecker 73].
The Society Equestrian Marshal bears: Sable, two tilting lances in saltire and in chief a chamfron Or.
Gisele Maria Overton bears: Per pale vert and purpure, a chamfron Or.
Constancia Tattersall bears: Argent goutty, on a chamfron azure a cross patonce argent.