1. An instrument for graphically recording variations of pressure of a fluid; especially, of blood in the vessels of a living animal; a recording manometer; also called kymographion.

Later used more widely; the instrument consists of a cylinder rotated by a clockwork or electric motor, together with a stylus designed to trace on a roll of paper wrapped around the cylinder a curve representing pressure variations or motion communicated to the stylus.

2. In radiology, an apparatus for recording the movement of the heart or other internal organs by moving an X-ray plate or film past one or more slits in a screen placed between it and the subject, so that movement of the organ in a direction parallel to a slit is recorded as a curve separating differently exposed portions of the radiograph.

A device for recording the movement of the heart or other types of motion on a single x-ray film.