stroboscope

/S T R OW1 B AH0 S K OW0 P/
noun
  1. 1

    Instrument for studying or observing periodic movement by rendering a moving body visible only at regular intervals.

  2. 2

    A lamp that produces short bursts of light that synchronizes with a camera shutter for photographing fast-moving objects.

  3. 3

    A photograph produced by such a machine.

Source: https://en.wiktionary.org/wiki/stroboscope