DictionaryplumbMeasuring weight
noun

plumb

A weight suspended on a line to check vertical alignment or depth.

The mason hangs a plumb beside the wall to check its alignment.

Etymology

The Latin word names lead, the metal traditionally used for the suspended weight. The material-name became the name of the measuring weight itself.

More examples

  • She waits for the plumb to stop swinging before taking a reading.
  • A plumb on a marked line helps measure the well's depth.
  • The toolbox holds two brass plumbs and a spool of string.

Forms

plumb · plumbs

Similar words

plumb bob
Specifically names the weight used to check vertical alignment.
plummet
Also names a suspended measuring weight, but is less common.