An Etymological Dictionary of Astronomy and Astrophysics

A balance used for weighing loads that has a two beams of different lengths.
The shorter beam has a hook or the like for holding the object to be weighed and the longer one supports a movable counterpoise that slides
to attain a balance.

Etymology (EN): → steel; yard, from M.E. yard(e), O.E. gerd “straight twig;” cognate with Du. gard, Ger. Gerte “rod.”

Etymology (PE): Qapân, from kapân “a large balance with one scale, being kept in equilibrium by a weight on the other end of the beam, a lever balance” (Steingass).