armature
A hidden framework or skeleton that supports or moves something.
An armature is the rotating part inside an electric motor or generator that contains coils of wire. When electricity flows through these coils, the armature spins, creating the motion that powers everything from toy cars to factory machines. In a generator, it works the opposite way: when you spin the armature, it generates electricity.
The word also refers to a supporting framework or skeleton that holds something up while you work on it. Sculptors build an armature from wire or wood before adding clay, giving their sculpture strength and shape. Stop-motion animators use metal armatures inside their clay characters so they can pose them frame by frame. Without the armature, a clay figure would just collapse into a blob.
Think of an armature as the bones beneath the surface, whether it's the spinning core of a motor or the hidden skeleton that keeps a sculpture standing. The framework might be invisible in the finished product, but it's doing essential work: providing structure, enabling movement, or making something possible that couldn't exist without it.