- a device formerly used for taking a series of instantaneous photographs of a rapidly moving object.
- a picture taken by such a device.
- a chronograph in which the tracing or record is made by a pencil of light on a sensitized surface.
- an instrument for measuring small intervals of time by the photographic trace of a pencil of light.
- an instrument for measuring very small time intervals by the trace made by a beam of light on a moving photographic film
