Fast Mash
- Plumb derives from Latin, plumbum, which meant “lead,” possibly from an ancient Iberian language, reflecting the source of lead for Romans and Greeks
- In construction, a plumb is a string fixed with a weight, often made out of lead, and was used as a reference for vertical lines; thus, out of plumb, among other expressions
- Nautically, a similar technology measured the depth of water; thus, plumbing the depths
- A plumber was originally a worker in lead and later referred to those who work with plumbing pipes, originally made out of lead
- Plunge and plummet are related
My mind’s been in the gutter. In the plumbing, more accurately. Well, technically, it’s my friend’s mine that’s gone cloacal. But I guess I started it. Prompted by my recent nautical-metrical streak, he requested plumb, adding: “I shudder to think of the implications that etymology may have for toilet repair professionals.” You asked for it, Shane. It’s actually pretty interesting.
Plumb
Plumb has many pipes. Today, perhaps we know it best as plumbing the depths, both figuratively and literally. And there’s a good reason we say that. On the sea, a plumb–also called a plummet–comprises a rope with a weight fixed to one end. It, well, plumbs the depths of the water. In fathoms, I suspect.
On land, a plumb–or a plumb line or plumb-bob–similarly comprised some string with a weight. It is a tool used in the building crafts as a vertical reference. Just as a level establishes a horizontal plane, so a plumb establishes the vertical or the perpendicular. The technology, apparently, dates back to ancient Egypt.
Here’s a basic demonstration of how the technology works from Denys Stocks’ Experiments in Egyptian Archaeology. It also doubles a good refresher in gravity:

If you ever tinkered around in your grandfather’s garage or got stuck in an antique mall with your grandmother, you might recognize the plumb-bob in its more recent, pointed form:

So, when something’s out of plumb? It’s not exactly vertical. When something’s plumb in the middle? It’s there, downright and square. When a person shows a lot of aplomb, they are assured, steadfast. That comes from the French à plomb, “to the plumb line” or “according to the plummet”: poised, straight, and balanced.
Now, these plumbs were frequently made out of lead, whose Latin word was plumbum. Thus the element’s chemical symbol, Pb. (Speaking of Roman lead, some ancient wines were even made by boiling grapes in lead pots, which added a sweetness to the vintage. Indeed, “sugar of lead” is another name for lead acetate.)
Latin’s plumbum could also refer to “rulers” for drawing vertical lines and the pencils used to draw them. And it could refer to pipes. Yes, plumbing pipes.
Plumbing
Did you catch this in the New York Times last Friday? It was a correction, originally appearing on Friday, September 27 in section A2:
An obituary on Sept. 20 about Hiroshi Yamauchi, the longtime president of Nintendo, included a quotation from a 1988 New York Times article that inaccurately described the Nintendo video game Super Mario Bros. 2. The brothers Mario and Luigi, who appear in this and other Nintendo games, are plumbers, not janitors.
Sorry, Mario.
But why are plumbers called so, anyways?
The Latin plumbum could refer to pipes because the Romans did use the malleable and durable metal in many of its water pipes. (The effects of lead poisoning in ancient Roman, from what I can tell, have been overstated, however.) Many of these pipes are famous for their inscriptions, bearing the names of the manufacturer, owner, and sometimes even the emperor himself, designed to prevent theft:

Originally, then, a plumber was a lead worker and plumbing was leadwork. The OED first attests the word in a compound, plumber house, in 1385, in the form of Plomberhous. Not too much later, a plumber came to signify “a person who fits or repairs the pipes (originally made of lead), fittings, and other apparatus relating to the water supply, sanitation, heating, etc., for a building” (OED).
But just in case you ever thought the OED was too starchy, it does have an entry for “plumber’s butt” and “plumber’s crack” (as well as Britain’s related “builder’s bum”). Yes, somebody had to–or got to, depending on how you want to look at it–define “plumber’s crack” as:
…the top of the buttocks and the cleft between them, as revealed when a person bends over or crouches down, or by low-cut or ill-fitting trousers…
And the definitive record of the English language attests “plumber’s butt” in the San Francisco Chronicle in 1990.
Warp Zone
Indeed, plumb enjoys a colorful life: In jazz slang, plumbing once referred to trumpets and trombones. In political jargon, plumbing refers to plugging up government leaks, thanks especially to Watergate, although the metaphor is much older. More jocularly, one’s plumbing can refer to what why we, well, need plumbing. And plumbum oscillans? It’s mock Latin, according to Partridge’s Slang, for “lead-swinging,” US naval officers’ playful term for “malingering” or “blatantly idling.” That’s my kind of slang: nerdy and Latinate.
And we have plunging neckline (attested, 1949) and take the plunge (1835). Or plummeting stock markets. (The sense of “falling rapidly” appears in the 1930s, probably from aviators). These, too, ultimately drain to plumbum.
So, can we plumb Latin’s plumb any deeper?
There is no certain origin for Latin’s plumbum. It might come from an ancient Iberian language; the OED notes that “lead came to the Greeks and Romans from Spain.” Shipley adds that “lead was mined in Spain as early as 2000 B.C.” And it’s probably related to Ancient Greek’s word for “lead,” μόλυβδος, or molybdos. Word-wise, that’s about as deep as this one sinks, far as I can tell.
But the metaphor of the plumb seems nearly as old as the technology itself. The Book of Amos in the Old Testament, which scholars believe was composed some time between the 8th and 6th centuries BC, features some rather dire consequences for being out of plumb with God. According to the “Vision of the Plummet,” Amos relates:
Then the Lord God showed me this: he was standing by a wall, plummet in hand. The Lord asked me, “What do you see, Amos?” And when I answered, “A plummet,” the Lord said:
“See, I will lay the plummet in the midst of my people Israel; I will forgive them no longer. The high places of Isaac shall be laid waste, and the sanctuaries of Israel made desolate; I will attack the house of Jeroboam with the sword.”
Um, ancient Israelites, I suppose the least of your worries is about how dense this plumb metaphor actually is.
Anyways, I speak often of etymology as “going down the rabbit hole.” But for those who grew up in the ’80s, perhaps we could swap out Lewis Carroll for Super Mario Bros. Sometimes a good word origin is like a “warp zone,” taking us to different worlds, one improbable pipe at a time.

Dear nephew,
I absolutely love your wordsmithing. Your father sent the link to me and I am delighted.
Thanks for your hard work. It is most entertaining for those of us who love language.
And congratulations on your impending union.
Warm regards, Uncle Tom (without a cabin)
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Thank you on all fronts! In this case, it’s good you have no cabin. You can take the boy out of Latin class but you can’t take Latin class out of the boy. Er, I’d guess a lot of former Latin students would happily disagree with that.
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“Ancient Greek’s word for “lead,” μόλυβδος, or molybdos. Word-wise, that’s about as deep as this one sinks, far as I can tell”
I think we can plumb the depths, forgive the obvious pun, of Ancient Greek: μόλυβδος (molybdos) a little deeper probably not to the very bottom of the deep blue sea but suggest that it is from Mycenaean Greek: mo-ri-wo-do “lead” (Greek/Linear B) which there seems to be evidence counter to the unnamed Iberian language origin theory that the word has been borrowed from an Anatolia Lydian word mariwda- “dark” as in the Lydian theonym mariwda(s)-k “the dark ones”.
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Linear B? Lydian theonym? First off, I think there are no better words to greet one first thing in the morning than those.
So, lead is known to be bluish when fresh cut and gray thereafter. Ancient languages did lump such shades into general words for “dark.” And a substantive formed on color property is common. For example, the origin of “gold” is indeed related to the origin of “yellow.”
What about the historical evidence for use of lead by Lydian and subsequent encounters with the ancient Greeks?
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I was wondering and interested to know what the Ancient Egyptians would have called “lead” but despite searching online I couldn’t really find anything so I had a look to see if I could find anything in the Coptic language being the end stage and inheritor of Ancient Egyptian and had a look what the other Semitic languages called ‘lead’:
Hebrew: עופרת (‘oferet) – derived from עפור (efer) and אפור (afor) meaning ‘grey’; ‘ashes’ אפר is possibly a loan word from Akkadian ‘epiru’ (earth, dust), Hebrew עפר (dust).
Arabic: رصاص (raSáS)
Amharic: እርሳስ (ʾərəsasə)
In the Coptic dictionary that I could find ‘lead’ is “taht” and “tath” (my rough transliteration) which doesn’t seem to tally with either Hebrew or Arabic?
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As usual, you are able to plumb depths deeper than I imagined the words could plunge. It seems that the salient characteristics–color, origin–win out in this name game.
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As we handcraft plumb bobs we have previously explored the origin of the word in brief and appreciate your more in depth discussion which we shared on our facebook page today. https://www.facebook.com/qualityinvermont/
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Lovely. Thanks for sharing, Marcy!
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