'Thulium' definitions:
Definition of 'thulium'
(from WordNet)
noun
A soft silvery metallic element of the rare earth group; isotope 170 emits X-rays and is used in small portable X-ray machines; it occurs in monazite and apatite and xenotime [syn: thulium, Tm, atomic number 69]
Definition of 'Thulium'
From: GCIDE
- Thulium \Thu"li*um\, n. [NL. See Thule.] (Chem.) A rare metallic element of the lanthanide group having atomic number 69, and atomic weight 168.93. It is found in the mineral gadolinite and other minerals, together with other rare earths. For more information see the data from ChemGlobe. [1913 Webster + PJC]
Definition of 'thulium'
From: Elements
- Symbol: Tm
- Atomic number: 69
- Atomic weight: 168.934
- Soft grey metallic element that belongs to the lanthanoids. One natural isotope exists, Tm-169, and seventeen artificial isotopes have been produced. No known uses for the element. Discovered in 1879 by Per Theodor Cleve.