Q: I’ve always believed cement is a binding agent that’s mixed with water, sand, and gravel to make concrete. But people now use the word “cement” where I’d use “concrete.” Have the two words become interchangeable? If so, is this a recent shift in the meaning of “cement”?
A: To someone in the construction business, cement and concrete are technically different: cement is used, as you point out, as a binding ingredient in what we now call concrete.
But the word “cement” is frequently used for “concrete” by people who aren’t in the building trades.
In fact, both The The American Heritage Dictionary of the English Language (4th ed.) and Merriam-Webster’s Collegiate Dictionary (11th ed.) give “concrete” as one of the standard English definitions of “cement.”
This should come as no surprise, since before the word “concrete” was invented, very similar stuff was called “cement” and nobody minded.
The word “cement” entered English sometime before 1300, more than 500 years before “concrete” showed up.
In its earliest usage, “cement” meant rubble mixed with lime and water to form mortar (a bonding agent used between brick, stone, etc.), according to the Chambers Dictionary of Etymology.
We got the word “cement” from the Old French ciment, but it’s ultimately from the Latin caementum, a contraction of caedimentum (rough cut stone or rubble). These are derived from the Latin verb caedere (to cut).
The substance we think of as concrete was familiar to the Romans, who used it to build the Forum, the Coliseum, the baths, and many other antiquities.
In this form of construction, which the Romans called opus caementicium, a concrete core was surrounded by brick walls.
If you’d like to read more about this, check out “Mechanical Characteristics of Roman Opus Caementicium,” a section in Fracture and Failure of Natural Building Stones, a 2006 book by Stavros K. Kourkoulis.
The word “concrete” entered English in the 15th century as an adjective meaning grown together, according to the Oxford English Dictionary, but that sense of the word is now considered obsolete.
The Latin ancestor of our English word is concretus, from the verb concrescere (to grow together).
Over the next few hundred years, the English adjective took on several other meanings, most of them describing something solid, material, or real (as opposed to abstract).
The use of “concrete” as a noun for construction material first showed up in English in the early 19th century.
The first citation in the OED is from an 1834 issue of London’s Architecture Magazine: “Making an artificial foundation of concrete (which has lately been done in many places).”
The next citation, from an 1836 entry in the Transactions of the Institute of British Architects, suggests that the term concrete came into general use “probably not longer than 15 or 20 years ago.”
So what do the words “cement” and “concrete” mean today?
Well, a contractor would use “cement” for that powdery mixture of ground limestone and clay that one buys in bags at a building supply store.
And the contractor would use “concrete” for the construction material one gets by mixing cement with sand, gravel, pebbles, broken stone, and so on.
But Merriam-Webster’s Dictionary of English Usage notes that “the use of cement to refer to various building materials now mostly known as concrete has been around for some 600 years.”
“Objections to its use, in other than technical contexts, in such combinations as ‘cement floors’ or ‘cement walks’ is pedantic,” M-W adds.
We generally stick with the technical distinction when referring to “cement” or “concrete,” but we don’t think it matters much.
Unless you’re trying to get a job at Home Depot or Lowe’s, use whichever word you want.
Like many language questions, this one doesn’t have a concrete answer!
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