Meaning of ATOMIC NUMBER 69

WordNet Dictionary
	Definition:		[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
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	Synonyms:		thulium, Tm
	See Also:		apatite, metal, metallic element, monazite, xenotime