stroboscope
Concise Oxford English Dictionary © 2008 Oxford University Press:
stroboscope /ˈstrəʊbəskəʊp/
▶noun Physics an instrument which shines a bright light at rapid intervals so that a moving or rotating object appears stationary.
– derivatives
stroboscopic adjective,
stroboscopically adverb.
stroboscopic adjective,
stroboscopically adverb.
'stroboscope' also found in these Oxford entries:

