ultramicroscope

/ˌʌltrəˈmaɪkrəˌskoʊp/
noun
  1. A microscope that uses a special lighting technique to see particles too small for a regular microscope.
    • In biology class, we learned how an ultramicroscope can detect particles smaller than a wavelength of light.
    • Ultramicroscopes help researchers study viruses and other tiny structures.
    • The scientist used an ultramicroscope to observe tiny dust particles in the air.