The couter is the defense for the elbow in a piece of plate armour. Initially just a curved piece of metal, as plate armor progressed the couter became an articulated joint.
Vambraces are generally called forearm guards, with or without separate couters. The highest forms of vambraces, in terms of art and utility, were developed in Italy and Germany during the Renaissance in Europe and by the Persian and Turkish armorers during the corresponding time period in Asia. Vambraces remained long in use after the high mark of Renaissance armor in Europe.