Definitions

from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun A bright, soft, silvery rare-earth metal obtained commercially from monazite, having an x-ray emitting isotope that is used in small portable medical x-ray units. Atomic number 69; atomic weight 168.934; melting point 1,545°C; boiling point 1,950°C; specific gravity 9.321 (at 25°C); valence 2, 3. cross-reference: Periodic Table.

from The Century Dictionary.

  • noun The name was given in 1879, by Cleve, to a supposed new element present in the compounds of Mosandu' s erbium extracted from gadolinite. The evidence of its existence was found in an examination of the absorption-spectra of products of the fractionation of erbium salt solutions, but it is very doubtful whether the separation is complete and whether thulium is to be considered as a distinct and single element.
  • noun A supposed element found in the mineral gadolinite. Its properties have not been ascertained, and its existence is doubtful.

from the GNU version of the Collaborative International Dictionary of English.

  • noun (Chem.) A rare metallic element of uncertain properties and identity, said to have been found in the mineral gadolinite.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun a metallic chemical element (symbol Tm) with an atomic number of 69.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • 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

Etymologies

from The American Heritage® Dictionary of the English Language, 4th Edition

[After Thule.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

Thule (as a poetic way to say Scandinavia) + -ium

Examples

Comments

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  • Tm

    December 1, 2007