1. 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
   - thulium, Tm

Type of: metal, metallic element

Part of: apatite, monazite, xenotime

• Chinese checkers
• Chinese chequers
• Chinese chestnut
• Chinese chive
• brown sugar
• Brown Swiss
• brown thrasher
• brown thrush
• brown trout
• Brown University
• brown-bag
• brown-black
• brown-gray
• brown-green
• brown-grey
• brown-haired
• brown-nose
• brown-purple
• brown-speckled
• brown-striped
• brown-tail moth
• Browne
• browned
• browned off
• brownfield