垂すい準じゅん

noun

plummet; plumb line

A weight suspended from a string used to establish a vertical reference line. This is a technical term in carpentry, surveying, and construction. The kanji 垂 (hang down) and 準 (standard) directly convey the meaning.

• 大だい工くは壁かべが垂すい直ちょくかどうかを確たしかめるために垂すい準じゅんを使つかった。

  The carpenter used a plumb line to check if the wall was vertical.