1. A weight on the end of a line, used to determine water depth.
2. A weight on the end of a line, used especially by masons and carpenters to establish a true vertical.
1. In a vertical or perpendicular line.
2. Informal Directly; squarely: fell plumb in the middle of the puddle.
3. also plum Informal Utterly; completely: plumb worn out. right
1. Exactly vertical. See Synonyms at vertical.
2. also plum Informal Utter; absolute; sheer: a plumb fool.
v. plumbed, plumb·ing, plumbs
1. To determine the depth of with a plumb; sound.
2. To test the verticality or alignment of with a plumb.
3. To straighten or make perpendicular: plumb up the wall.
4. To examine closely or deeply; probe: "Shallow ideas are plumbed and discarded" (Gilbert Highet).
5. To seal with lead.
6. To outfit with or connect to a plumbing system: plumbed the utility closet so a washing machine could be installed.
To work as a plumber.
off/out of plumb
[Middle English, lead, a plumb, from Old French plomb, from Latin plumbum, lead.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.