episcotister

American  

[uh-pis-kuh-tis-ter, ep-i-skuh-tis-ter] / əˈpɪs kəˌtɪs tər, ˌɛp ɪ skəˈtɪs tər /

Or episkotister

noun

1. a disk with a sector removed that when rotated in front of a light source allows the periodic passage of flashes of light: used in studying the motion of a body.

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Etymology

Origin of episcotister

1900–05; < Greek episkot ( ízein ) to overshadow ( see epi-, scotia, -ize) + -ist + -er ¹