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plumb line

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noun
  1. a cord with a lead bob attached to one end, used to determine perpendicularity, the depth of water, etc.Compare plumb(def 1).
  2. plumb rule.
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Origin of plumb line

First recorded in 1530–40
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for plumb line

Historical Examples

  • Will and the Professor were by the ice shaft, watching the plumb-line.

    Doctor Jones' Picnic

    S. E. Chapman

  • “Maybe you did not use the plumb-line, Master Leo,” observed Jack.

    In the Wilds of Africa

    W.H.G. Kingston

  • In the game way the stem and stern were measured with a plumb-line.

    In the Wilds of Africa

    W.H.G. Kingston

  • When I comes to rekillect how an' where he got that 'ere back, it looks to me like a plumb-line.

  • There is no plumb-line to measure the depths of thy shame, so deep is that abyss.

    The Valkyries

    Edward Frederic Benson


British Dictionary definitions for plumb line

plumb line

noun
  1. a string with a metal weight at one end that, when suspended, points directly towards the earth's centre of gravity and so is used to determine verticality, the depth of water, etc
  2. another name for plumb rule
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Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

plumb line in Science

plumb line

[plŭm]
  1. A line regarded as directed exactly toward the Earth's center of gravity.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.