plumb line

noun

Definition of plumb line

1 : a line (as of cord) that has at one end a weight (such as a plumb bob) and is used especially to determine verticality
2 : a line directed to the center of gravity of the earth : a vertical line

Recent Examples of plumb line from the Web

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'plumb line.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of plumb line

15th century

in the meaning defined at sense 1

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PLUMB LINE Defined for English Language Learners

plumb line

Definition of plumb line for English Language Learners

  • : a tool that consists of a small, heavy object attached to a string or rope and that is used especially to see if something (such as a wall) is perfectly vertical



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