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Từ điển Oxford Learners Wordfinder Dictionary
atomic number 69
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 • Hypernyms: metallic element, metal • Substance Holonyms: apatite, monazite, xenotime
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