ˈkär-, ˈkər- noun
Usage: usually capitalized K
Etymology: after John Kerr died 1907 Scottish physicist
: a cell that contains electrodes immersed in nitrobenzene or other liquid, that exhibits double refraction in a high degree and with short time lag, and that is used in devices where the intensity of light is to be changed rapidly in accordance with the voltage applied to the electrodes (as in the recording of sound tracks for motion pictures) — compare kerr effect 1