Rare-Earth Element, Transition Metal, Used in Leds
Puzzle 20 of Spy World Medium Pack
Question is: Rare-Earth Element, Transition Metal, Used in Leds
and the answer is: YTTRIUM
Word Meaning:
YTTRIUM — A silvery metallic chemical element with an atomic number of 39, mainly found in combination with lanthanide elements in rare earth minerals.
Definitions from Wiktionary.