/ ˈθuːliəm; NAmE ; BrE also ˈθjuː-/ noun
[ U ] ( symb Tm ) a chemical element. Thulium is a soft silver-white metal.
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WORD ORIGIN
late 19th cent.: modern Latin , from Latin Thule (a country described by the ancient Greek explorer Pytheas), from Greek Thoulē , of unknown origin.