plumb rule

A narrow board with a plumb line. It is used by masons, carpenters, ., for proving the perpendicularity of work. plumber-block, s. [PILLOW-BLOCK.] plumber's force-pump, subst . A pump used by plumbers for testing pipe or withdrawing obstacles from a gorged pipe. It may be attached to the delivery end of the pipe so as to act by suction, or may be applied elsewhere, effecting the desired object by hydraulic pre ure.