You searched for: “electron dense
electron-dense, electron dense
1. In electron microscopy, having a density that prevents penetration by electrons.
2. Characterized by being relatively opaque to the passage of the electron beam in an electron microscope.

Such an object will appear as a dark area on the viewing screen and photographic prints.

This entry is located in the following units: electro-, electr-, electri- (page 56) -tron, -tronic, -tronics + (page 5)