Didymium is used for coloring glass. Didymium enhancing filters are used in photography. "Enhancing" modifies "filters" in that phrase; the filters boost the red-orange colors.

Didymium-tinted lenses are used in scientific research as well. Separately, the word is used in botany for certain "didymous" plants that appear in pairs.

Chemical symbol is/was Di.

Di*dym"i*um (?), n. [NL., fr. Gr. twin.] Chem.

A rare metallic substance usually associated with the metal cerium; -- hence its name. It was formerly supposed to be an element, but has since been found to consist of two simpler elementary substances, neodymium and praseodymium. See Neodymium, and Praseodymium.

 

© Webster 1913.