Source : Webster's Revised Unabridged Dictionary (1913)

Magnify \Mag"ni*fy\, v. i.
   1. To have the power of causing objects to appear larger than
      they really are; to increase the apparent dimensions of
      objects; as, some lenses magnify but little.

   2. To have effect; to be of importance or significance. [Cant
      & Obs.] --Spectator.

   {Magnifying glass}, a lens which magnifies the apparent
      dimensions of objects seen through it.

Source : WordNet®

magnifying glass
     n : 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}]