1. The study of materials by means of the electron microscope.
2. Referring to a microscope in which an electron beam replaces light to form an image.
3. A technique using an electron microscope in which a beam of electrons is focused by an electromagnetic lens and directed onto an extremely thin specimen.

The emerging electrons are focused and directed by a second lens onto a fluorescent screen.

The magnified image which is produced is 1000 times greater than that produced by an optic microscope and well resolved, but it is two-dimensional because of the thinness of the specimen.