from The Century Dictionary.
- noun A perspective glass fitted with a mirror set at an angle, designed for viewing objects that do not lie directly before the eye: so named from its possible use in warfare to observe the motions of the enemy from behind defenses.
from the GNU version of the Collaborative International Dictionary of English.
- noun An opera glass or field glass with an oblique mirror arranged for seeing objects that do not lie directly before the eye; -- called also
diagonal opera glass, or side opera glass.
from Wiktionary, Creative Commons Attribution/Share-Alike License.
- noun An
opera glassor field glasswith an oblique mirrorarranged for seeing objects that do not lie directly before the eye.
from Wiktionary, Creative Commons Attribution/Share-Alike License
Ancient Greek for "war" + -scope: compare French polémoscope.
Lucy, is what is called a polemoscope -- that is to say, an instrument for observations in war. "