'Tachistoscope' definitions:

Definition of 'tachistoscope'

noun

Scientific instrument used by psychologists; presents visual stimuli for brief exposures [syn: tachistoscope, t-scope]

From: GCIDE

Tachistoscope \Ta*chis"to*scope\, n. [Gr. ta`chistos, superl. of tachy`s swift + -scope.] (Physiol.) An apparatus for exposing briefly to view a screen bearing letters or figures. It is used in studying the range of attention, or the power of distinguishing separate objects in a single impression. [Webster 1913 Suppl.]