The Collaborative International Dictionary of English v.0.48:

magnifying glass \magnifying glass\ n.
   A single convex lens which magnifies the apparent dimensions
   of objects seen through it, and is used to produce an
   enlarged image.

   Syn: hand glass.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

magnifying glass
    n 1: light microscope consisting of a single convex lens that is
         used to produce an enlarged image; "the magnifying glass
         was invented by Roger Bacon in 1250" [syn: hand glass,
         simple microscope, magnifying glass]

Moby Thesaurus II by Grady Ward, 1.0:

27 Moby Thesaurus words for "magnifying glass":
   achromatic lens, astigmatic lens, burning glass, camera,
   coated lens, concave lens, concavo-convex lens, condenser,
   convex lens, eyeglass, eyepiece, glass, hand lens, lens, magnifier,
   meniscus, object glass, objective, objective prism, ocular, prism,
   reader, reading glass, telephoto lens, toric lens, varifocal lens,
   zoom lens