Pŏl'y-ŏp'tron or Pŏl'y-ŏp'trum, n.

noun

n. [Gr. πολύς, many, and ὁρᾶν, future, ὄψομαι, from root ὀπτεῖν, to see; Fr. polyoptre.] (Opt.) A glass through which objects appear multiplied, but diminished.