plumb

Etymology

It is inherited from Middle English plum, also plom and plumbe,^[2][3][4][5] borrowed from Anglo-Norman plom, also plombe and plumb, and Middle French plom,^[6] and directly borrowed from Latin plumbum (“lead”).^[6][4][2] In Old French the word is recorded for the metal from the end of the 11th century, and for the builder's weight in 1260;^[6] the Anglo-Norman noun is recorded from the first third of the 12th century.^[7] Several dictionaries posit an unattested Old French *plombe,^[8][9][10] from Vulgar Latin *plumba,^[8][11] and others an unattested plomb from plon;^[3][12] the MED names plomee.^[2] The -b was restored in English after about 1400.^[10] The adjective and adverb come from the noun,^{[6][4][3][13]} the adverb compared with a plon (“vertically, straight down”),^[6][2] and the verb comes from all three,^[6] partly after plommer in the sense of weighting with lead.^[6][13] The verb's plumbing sense is a back-formation from plumber.^[14][5][13] The Latin noun is of disputed origin.^[6][15] The OED takes it as a loanword from the same source as Ancient Greek μόλυβδος (mólubdos, “lead”), probably an Iberian language, since lead first reached the Greeks and Romans from Spain;^[6] Barnhart, Klein and Merriam-Webster Unabridged also connect the Greek word.^[4][5][3] De Vaan, following Beekes, thinks the Greek connection unlikely and a link with the Celtic word behind Old Irish lúaide (“lead”) more probable, though Latin plumbum cannot regularly come from the same root; he suggests that it may be a loanword from another language, pointing to a Berber word for lead.^[15][10]

Earliest recorded meaning

The lead weight on a line used to find the vertical: before 1325, in the Cursor Mundi, in a manuscript of before 1400.^[6][4] Etymonline has the early 14th century for this sense and the mid-14th for the metal itself,^[10] which the MED records as a sense of Middle English plum.^[2]

Semantic evolution

The noun began with lumps of lead put to particular uses: the builder's weight, a sounding lead from about 1425 to 1864, a missile or a weight on a weapon or whip from before 1425 to 1867, and the weight on a clock or fishing line from about 1450 to 1778.^[6] Its Scottish and northern use for a deep hole in a river bed is recorded from about 1780.^[6] Ayto derives the verbal sense "sound the depths" and the adverbial "exactly" from the uses of a plumb line.^[9] The adverb meant "straight down" from about 1425, in the Laud Troy Book,^[6][2] and "exactly" from 1601, in Holland's Pliny.^[6] Etymonline sees the idea of exact measurement behind the intensifying use, "completely",^[10] which the OED records from 1588,^[6] and which is now chiefly North American and colloquial, as is the adjective "downright", from 1748, in Richardson's Clarissa.^[6][4] The verb first meant to sink like lead, late in the 14th century;^[10][4][6] a fishing treatise of about 1450 has lines "plomed with leyd".^[2] Measuring depth is recorded from before 1568,^[6][4] and the figurative "get to the bottom of" from 1599,^[6][10] the source of plumb the depths.^[16] Testing for the vertical came only in 1711.^[6] The last addition is the sense of fitting pipes: a building could be plumbed by 1859,^[6] and Etymonline dates working as a plumber to 1889.^[10] Plumbers were once simply workers in lead, and water pipes were made of it.^[9][16] In slang the verb has meant to fool, from 1804, and to have sexual intercourse, from 1927.^[17]

Timeline

• before 1325 – noun, the lead weight of a plumb line, as plum.^[6][4]
• 1392 – verb, plumen, to immerse.^[4] The OED first has the verb before 1425, to sink like a plummet.^[6]
• c. 1425 – adverb, vertically, straight down.^[6] Barnhart has about 1400.^[4]
• c. 1425 – a sounding lead (last recorded 1864).^[6]
• c. 1450 – to weight a fishing line with lead.^[6][2]
• before 1460 – adjective, vertical, as plom.^[6][4]
• 1538 – plumb line.^[4]
• before 1568 – to measure the depth of water.^[6][4]
• 1588 – adverb, completely, absolutely.^[6]
• 1599 – figurative, to get to the bottom of.^[6]
• 1601 – adverb, exactly in a direction or position.^[6]
• 1711 – to make vertical, to check against a plumb line.^[6]
• 1748 – noun, the vertical, as in out of plumb; adjective, downright, absolute.^[6]
• 1859 – to provide a building with plumbing.^[6]
• 1902 – adjective, in cricket, of a pitch, level and true.^[6]

Meanings

Noun

1. A weight, usually of lead, hung on a line to show the vertical or to measure the depth of water; a plumb bob or plummet.^[12][3][6]
2. The vertical, or the state of being correctly aligned, especially in out of plumb: The old gatepost is badly out of plumb.^[12][6]
3. (obsolete, before 1425–1867) A ball of lead used as a missile.^[6][3]

Adjective

1. Exactly vertical: Check that the door frame is plumb.^[3][6]
2. (informal, chiefly US) Downright, utter: a plumb waste of money.^[12][6][3]
3. (cricket) Of a wicket or pitch, level and true.^[3][6]

Adverb

1. In a vertical line; straight down.^[12][3][6]
2. Exactly, precisely: The ball landed plumb in the middle of the green.^[12][3][6]
3. (informal, chiefly US) Completely, absolutely: By evening we were plumb tired out.^[12][6][3]

Verb

1. To measure the depth of water with a weighted line; to sound.^[3][6]
2. To examine deeply, or to reach the lowest point of something: The novel plumbs the depths of his grief.^[3][6][13]
3. To test with a plumb line, or to make vertical.^[3][6]
4. To provide a building or room with plumbing.^[6][13]
5. (obsolete, c. 1450–1811) To weight with lead.^[6][3]

Word family

• plumbable
• plumbless
• plumbness
• unplumb
• replumb
• plumb bob
• plumb line
• plumb rule

Related words

• aplomb
• plumber
• plummet
• plunge
• plumbago
• plumbing

References

1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h Kurath, Hans; Kuhn, Sherman M.; Lewis, Robert E., eds. (1952–2001), Middle English Dictionary, Ann Arbor: University of Michigan Press; online edition ed. Frances McSparran et al. (2000–2018)
3. ^ a b c d e f g h i j k l m n o p Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
4. ^ a b c d e f g h i j k l m n Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
5. ^ a b c Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
6. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
7. ^ Anglo-Norman Dictionary (AND2), Aberystwyth University, anglo-norman.net (2nd ed., 2005–)
8. ^ a b Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
9. ^ a b c Ayto, John (2005), Word Origins: The Secret Histories of English Words from A to Z, 2nd ed., London: A & C Black
10. ^ a b c d e f g h Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
11. ^ Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
12. ^ a b c d e f g Collins English Dictionary (2023), Glasgow: HarperCollins
13. ^ a b c d e Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
14. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
15. ^ a b de Vaan, Michiel (2008), Etymological Dictionary of Latin and the other Italic Languages, Leiden Indo-European Etymological Dictionary Series 7, Leiden; Boston: Brill
16. ^ a b Cresswell, Julia (2021), Oxford Dictionary of Word Origins, 3rd ed., Oxford: Oxford University Press
17. ^ Green, Jonathon (2010), Green's Dictionary of Slang, London: Chambers; digital ed. 2016–, https://greensdictofslang.com