ul·tra·mi·cro·scope 
(ŭl′trə-mīkrə-skōp′)
(ŭl′trə-mīkrə-skōp′)n.
A microscope with high-intensity illumination used to study very minute objects, such as colloidal particles that scatter the light and appear as bright spots against a dark background.
ul′tra·mi·crosco·py (-krŏskə-pē) n.