English version

plumb line in Tools topic

From Longman Dictionary of Contemporary Englishplumb lineˈplumb line noun [countable]  TZa piece of string with a small heavy object tied to one end, used for measuring the depth of water, or for checking whether something such as a wall is built exactly upright
Examples from the Corpus
plumb lineIf any walls appear to lean, check by going back to the nearest upper window and drop a plumb line down.But again, as with the lintels, the union did not allow the bricklayers to use a plumb line.