Source : Webster's Revised Unabridged Dictionary (1913)

Trone \Trone\, Trones \Trones\, n. [LL. trona, fr. L. trutina a
   balance; cf. Gr. ?.]
   1. A steelyard. [Prov. Eng.]

   2. A form of weighing machine for heavy wares, consisting of
      two horizontal bars crossing each other, beaked at the
      extremities, and supported by a wooden pillar. It is now
      mostly disused. [Scot.] --Jamieson.

   {Trone stone}, a weight equivalent to nineteen and a half
      pounds. [Scot.]

   {Trone weight}, a weight formerly used in Scotland, in which
      a pound varied from 21 to 28 ounces avoirdupois.