Main Entry: yt·tri·um

Pronunciation: \ˈi-trē-əm\

Function: noun

Etymology: New Latin, from yttria yttrium oxide (Y₂O₃), irregular from Ytterby, town in southern Sweden

Date: 1814

: a metallic element usually included in the rare-earth group that occurs usually with other rare earth elements in minerals and is used especially in phosphors, YAG lasers, and superalloys — see element table