from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A bright, silvery rare-earth element 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 1,727°C; specific gravity 9.3; valence 2, 3. See Table at element.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. a metallic chemical element (symbol Tm) with an atomic number of 69.
from the GNU version of the Collaborative International Dictionary of English
- n. A rare metallic element of uncertain properties and identity, said to have been found in the mineral gadolinite.
from The Century Dictionary and Cyclopedia
- n. 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.
- n. A supposed element found in the mineral gadolinite. Its properties have not been ascertained, and its existence is doubtful.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. 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
After Thule 1.(American Heritage® Dictionary of the English Language, Fourth Edition)
Thule (as a poetic way to say Scandinavia) + -ium (Wiktionary)