Definition of "field-glass" [field-glass]

• A kind of binocular telescope in the form of a large operaglass, provided with a case slung from a strap, so that it can be conveniently carried. These glasses are used especially by military men and tourists. (noun)
• A small achromatic telescope, usually from 20 to 24 inches long, and having from 3 to 6 joints of the kind known as telescopic. (noun)
• That one of the two lenses forming the eyepiece of an astronomical telescope or of a compound microscope which is the nearer to the object-glass, the other being the eye-glass. Also called field-lens. (noun)

The Century Dictionary (Public Domain)

• "This caused a halt, and having hurriedly re-capped our guns and six-shooters, thus preparing for the worst, I took a look at the band through my field-glass."
• "I did not indulge in this confidence, however; for, with the excellent field-glass I had, I could distinctly see long columns of French troops moving to their right, for the apparent purpose of making a vigorous fight on that flank; and I thought it more than likely that their artillery would be heard from before the Germans could gain the coveted ridge."
• "The Emperor had been the first, as early as mid-day, to descry with his field-glass, on the extreme horizon, something which had attracted his attention."