Elementymology & Elements Multidict

memory peg	Gray-white metal melting point 1412 °C; 2574 °F boiling point 2562 °C; 4644 °F density 8.55 g/cc; 533.76 pounds/cubic foot
1886 François Lecoq de Boisbaudran, France
δυσπροσιτος (dysprositos) = hard to obtain (Greek)

The rare earth erbia, as described by the Swedish chemist Nils Johan Berlin (see Erbium) was examined by Jacques-Louis Soret in 1878 and by Per Theodor Cleve in 1879 (note). They both found a new earth, did not name it (in literature is is called Soret’s X or Element X), Cleve named it holmia (see Holmium).

This new earth was impure too and split by François Lecoq de Boisbaudran in 1886 into true holmia and a new oxide, which he named dysprosia (note), derived from the Greek δυσπροσιτος [dysprositos] = hard to obtain, because of the difficulty involved in its detection and isolation.

Lecoq described in 1886 the elements Zα and Zβ, the former probably identical with Dysprosium (note)

According to a list of the US government a synonym name is Demonium. I have not found further details.

John and Gordon Marks suggested in 1994 the name Suevium (Su), together with Norium (=Terbium) after Norway and Sweden where the lanthanides were discovered. The Marks brothers found the old names ugly and confusing. They offered alternative names that are equivalent contemporary (at the time and place of discovery) metaphors, both more euphonious and more memorable (note).

See also: Chronological list of discovery of the rare earths and their names

• Mary Elvira Weeks, Discovery of the Elements, comp. rev. by Henry M. Leicester (Easton, Pa.: Journal of Chemical Education, 1968), pp. 667-699.
• Seltene Erden. Gmelins Handbuch der anorganische Chemie, 8. Aufl.; System-Nummer 39 (1938).