A goniometer is an instrument that either measures angles or allows an object to be rotated to a precise angular position.
There are many types, each specialised for its particular application.
Goniometers are used in crystallography for measuring angles between crystal faces. They are also used in X-ray diffraction to rotate the samples. Other versions range from devices which measure human joint movement to ones which determine the angle of contact between a liquid droplet and a flat substrate.
