Object glass Meaning, Definition & Usage

  1. noun the lens or system of lenses in a telescope or microscope that is nearest the object being viewed
    objective; objective lens; object lens.

WordNet

Definitions
  1. the lens, or system of lenses, placed at the end of a telescope, microscope, etc., which is toward the object. Its office is to form an image of the object, which is then viewed by the eyepiece. Called also objective. See Illust. of Microscope.

Webster 1913