\Steel"yard\, n. [So named from a place in London
called the Steelyard, which was a yard in which steel was
sold.]
A form of balance in which the body to be weighed is
suspended from the shorter arm of a lever, which turns on a
fulcrum, and a counterpoise is caused to slide upon the
longer arm to produce equilibrium, its place upon this arm
(which is notched or graduated) indicating the weight; a
Roman balance; -- very commonly used also in the plural form,
steelyards.