Definition of "opera-glass" []

• A small binocular non-inverting telescope, of a low magnifying power, designed to be used to aid vision in the theater; a lorgnette. (noun)

The Century Dictionary (Public Domain)

• "I scanned the house meanwhile through my opera-glass, and seemed to lend an inattentive ear to the secretary; but, between ourselves, I was wretched at having burnt his letter."
• "He would give no special heed to any woman whatever; and the better to guard against temptation, he used a cunningly contrived opera-glass which destroyed the harmony of the fairest features by hideous distortions."
• "Often these dramas are played so naturally and with such a varnish of good taste that even I have to rub the lens of my opera-glass to see to the bottom of them."