Share this entry
thulium Syllabification: thu·li·um
Pronunciation: /ˈTH(y)o͞olēəm/

Definition of thulium in English:


The chemical element of atomic number 69, a soft silvery-white metal of the lanthanide series. (Symbol: Tm)
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.

Definition of thulium in:
Share this entry

What do you find interesting about this word or phrase?

Comments that don't adhere to our Community Guidelines may be moderated or removed.

Subscribe to remove adverts and access premium resources