diascope

plural diascopes

1. A projector used for projecting transparencies.

   When it is used to project a slide then at serves as a diascope.

   2004, M. Vanaja, Methods Of Teaching Physics, →ISBN, page 90

   2 more examples

   The diascope test pattern reference for automatic setup is a transparency (Figure 3), built into all TK47B lenses.

   1982, International Broadcast Engineer: IBE. - Volumes 181-196

   The diascope passes light through the two-dimensional object (such as a photographic transparency, slide, or film) and uses a converging projection lens to form an enlarged image on a distant screen.

   2010, Elizabeth A. Martin, A Dictionary of Science, →ISBN, page 663

2. a slide viewer, a device for looking at small transparent images.
3. medicineA flat piece of glass or transparent plastic, used to examine lesions in the skin

   The diascope (a flat piece of glass) was used to press out the blood and expose the apple-jelly points of marginal growth.

   1898, “Cutaneous Tuberculosis by Auto-infection”, in Indiana Medical Journal