At any rate, let's get on with the A to Z!
Rerebrace - Plate that covers the section of upper arm from elbow to area covered by shoulder armour.
Rondel Dagger - Then we have the rondel dagger or roundel dagger was a type of stiff-bladed dagger in Europe in the late Middle Ages (from the 14th century onwards), used by a variety of people from merchants to knights. It was worn at the waist and might be used as a utility tool, or worn into battle or a jousting tournament as a side-arm. Rondel daggers were ideal in battle for puncturing chain mail, and although they would not have been able to punch through plate armour, they could be forced between the joints in a suit of armour and helmets. This was often the only way in which a heavily armoured knight could be killed.