#troy_unit  any of the unit of the troy system of weights
  supertype:  weight_unit  a unit used to measure weight; "he placed two weights in the scale pan"
  subtype:  grain.troy_unit  pennyweight  apothecaries'_ounce  troy_pound
  part of:  troy_weight__troy  a system of weights used for precious metals and gemstones; based on a 12-ounce pound and an ounce of 480 grains

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