(n)optical device consisting of a transparent cell with two electrodes between two polarizing media; passes light only if the two planes of polarization are parallel; used as a high-speed shutter or to modulate a laser beam
n. [ Boer D. knopkirie, fr. D. knop-hout, knotty stick + Hottentot kïrri club. ] A short wooden club with a knobbed end used as a missile weapon by Kafir and other native tribes of South Africa. [ Webster 1913 Suppl. ]