1) Western plate armour 
The couter (also spelled `cowter`) 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. In fighting reenactment groups such as the Society for Creative Anachronisms, a couter/cowter is often called an elbow cop. ...
armor for the elbow
Couter was old British slang for one pound sterling.
Elbow defence for a plate armour.
a piece of plate armor for the elbow. See diag. under