#avoirdupois_unit__avoirdupoisunit  any of the units of the avoirdupois system of weights
  supertype:  mass_unit  a unit of measurement for mass
  subtype:  grain.avoirdupois_unit  dram  ounce  lb  stone.avoirdupois_unit  quarter.avoirdupois_unit  long_hundredweight  short_hundredweight  long_ton  short_ton  kiloton.avoirdupois_unit  megaton.avoirdupois_unit
  part of:  English_system__British_system  a system of weights and measures based on the foot and pound and second
  part of:  avoirdupois_weight__avoirdupoisweight__avoirdupois__avoirdupoi  a system of weights based on the 16-ounce pound (or 7,000 grains)

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