(1):
(n.) A spy-glass; a looking-glass.
(2):
(n.) Fig.: An aid to the intellectual sight.
(3):
(n.) An optical instrument consisting of two lenses set in a light frame, and worn to assist sight, to obviate some defect in the organs of vision, or to shield the eyes from bright light.
(4):
(n.) Something exhibited to view; usually, something presented to view as extraordinary, or as unusual and worthy of special notice; a remarkable or noteworthy sight; a show; a pageant; a gazingstock.