trones, n. [LL. trona, fr. L. trutina a balance; cf. Gr. .].
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.
A steelyard. [1913 Webster]
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. Jamieson. [1913 Webster]