An ultramicroscope is a microscope with a system of illumination that allows viewing of tiny particles. When the diameter of a particle is below or near the wavelength of visible light (around 500 nanometers), the particle cannot be seen in a light microscope with the usual method of illumination. The ultramicroscope system is based on light scatt...
An instrument for detecting very small particles by focussing a beam of light in a liquid obliquely to the direction of observation.
instrument for viewing extremely small objects
microscope arrangement used to study colloidal-size particles that are too small to be visible in an ordinary light microscope. The particles, ... [3 related articles]
<instrument, microscopy> A term applied to particles less than 0.1 ~m in diameter, hence too small to be truly resolved by the light micro- scope. Under the ultramicroscope they look like stars in the sky. Their differences in size are merely indicated by differences in brightness. ... (05 Aug 1998) ... 
Type: Term Pronunciation: ŭl′tră-mī′krō-skōp Definitions: 1. A microscope that uses refracted light for visualizing objects not visible with the ordinary microscope when direct light is used.
[n] - light microscope that uses scattered light to show particles too small to see with ordinary microscopes
dark-field microscope noun light microscope that uses scattered light to show particles too small to see with ordinary microscopes
an instrument that uses scattering phenomena to detect the position of objects too small to be seen by an ordinary microscope.