ˌepəskōˈtistə(r) noun
( -s )
Etymology: from (assumed) Greek episkotistos (verbal of Greek episkotizein to shadow, darken, from epi- + skotizein to darken, from skotos dark + -izein -ize) + English -er — more at shade
: a device for reducing the intensity of light in known ratio by means of rapidly rotating opaque and transparent sectors