- a microscope of extremely high power that uses beams of electrons focused by magnetic lenses instead of rays of light, the magnified image being formed on a fluorescent screen or recorded on a photographic plate: its magnification is substantially greater than that of any optical microscope.
- a powerful type of microscope that uses electrons, rather than light, and electron lenses to produce a magnified image
- Any of a class of microscopes that use electrons rather than visible light to produce magnified images, especially of objects having dimensions smaller than the wavelengths of visible light, with linear magnification approaching or exceeding one million (106).
- A microscope that produces images of extremely small objects by using beams of electrons rather than visible light. Since electrons have a much shorter wavelength than light, the use of electron beams rather than light beams can resolve much finer structural details in the sample. Electrons are beamed at the sample and focused by magnets; a detector then converts the refracted or reflected beams into a black and white image. See also scanning electron microscope.