Definition of thulium in English:


Syllabification: thu·li·um
Pronunciation: /ˈTH(y)o͞olēəm


The chemical element of atomic number 69, a soft silvery-white metal of the lanthanide series. (Symbol: Tm)
More example sentences
  • Each segment contains small amounts of ions of relatively rare metals, such as dysprosium, thulium, and cerium, which fluoresce in different colors.
  • The pure metal can be produced by treating thulium fluoride with calcium metal.
  • The main rare-earth ions used are thulium (for devices operating at 1450 to 1510 nm) and erbium.


late 19th century: modern Latin, from Latin Thule Thule (sense 1), from Greek Thoulē, of unknown origin.

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Word of the day demoralize
Pronunciation: dəˈmôrəˌlīz
cause (someone) to lose confidence or hope; dispirit