"optical instrument which by means of a lens or lenses magnifies and renders visible minute objects or details of visible bodies," 1650s, from Modern Latin microscopium, literally "an instrument for viewing what is small;" see micro- + -scope. The dim southern constellation Microscopium was among those introduced by La Caille in 1752.
[instrument for viewing] 1872, shortened from telescope, microscope, etc., in which the element (Latinized) is from Greek skopein "to look" (from PIE root *spek- "to observe"). Earlier used as a shortening of horoscope (c. 1600). Extended to radar screens, etc., by 1945 as a shortening of oscilloscope.