thulium

[thoo-lee-uh m]

noun Chemistry.

a rare-earth metallic element found in the minerals euxenite, gadolinite, etc. Symbol: Tm; atomic weight: 168.934; atomic number: 69; specific gravity: 9.32.

Origin of thulium

From New Latin, dating back to 1875–80; see origin at Thule, -ium

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for thulium

thulium

noun

a malleable ductile silvery-grey element occurring principally in monazite. The radioisotope thulium-170 is used as an electron source in portable X-ray units. Symbol: Tm; atomic no: 69; atomic wt: 168.93421; valency: 3; relative density: 9.321; melting pt: 1545°C; boiling pt: 1950°C

Word Origin for thulium

C19: New Latin, from Thule + -ium

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

thulium in Medicine

thulium

[thōō′lē-əm]

n. Symbol Tm

A rare-earth element having an x-ray emitting isotope that is used in small portable medical x-ray units. Atomic number 69.

thulium in Science

thulium

[thōō′lē-əm]

Tm

A soft, silver-gray metallic element of the lanthanide series. One of its artificial radioactive isotopes is used as a radiation source in small, portable x-ray machines. 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 Periodic Table.