Armature

Armature originally meant a 'protective covering', and hence in biology it means the protective covering of an animal or plant. It was formerly in use in the sense of 'armour' which has now become archaic. Later it got an additional meaning 'a keeper of a magnet' which extended to the rotating coil or coils of a dynamo or electric motor, and then came to mean any moving part of an electrical machine in which a voltage is induced by a magnetic field.

A metal framework on which a sculpture is molded with clay or similar material also came to be known as armature. Any formal structure or framework, especially of a literary work is also called armature.