dysprosium

UK: /dɪsˈprəʊsɪəm/ US: (dis prō′sē əm, -shē-)

WordReference Random House Unabridged Dictionary of American English © 2025

dys•pro•si•um  (dis prō′sē əm, -shē-), n. [Chem.]

1. Chemistry a rare-earth metallic element, highly reactive and paramagnetic, found in small amounts in various rare-earth minerals, as euxenite and monazite: used to absorb neutrons in nuclear reactors. Symbol: Dy;
   at. wt.: 162.50;
   at. no.: 66.

• Greek dysprós(itos) hard to get at (dys- dys- + pros- to + itós, past participle of iénai to go) + -ium
• Neo-Latin
• 1885–90

Collins Concise English Dictionary © HarperCollins Publishers::

dysprosium / dɪsˈprəʊsɪəm/ noun

1. a soft silvery-white metallic element of the lanthanide series: used in laser materials and as a neutron absorber in nuclear control rods. Symbol: Dy; atomic no: 66; atomic wt: 162.50; valency: 3; relative density: 8.551; melting pt: 1412°C; boiling pt: 2567°C

Etymology: 20th Century: New Latin, from Greek dusprositos difficult to get near + -ium