A horseshoe is a U-shaped metal plate, nailed to a horse’s hoof for its protection. It’s an ancient heraldic charge, dating from c.1280, in the canting arms of Ferrers [ANA2 216]. The horseshoe has its opening to base by default; it is conventionally drawn with seven nail-holes. See also axle bracket.
Caitilín Mhór bears: Per pale azure and Or, a horseshoe inverted counterchanged.
Joanna of the Plains bears: Sable, four horseshoes openings to dexter two and two Or.
Selfran the Singer bears: Azure, in cross five horseshoes inverted Or.