Q: In John Dos Passos’s U.S.A. trilogy, a colonel appears, “his waxed mustaches bristling with fury.” I often see “mustaches” in old books, but not in newer ones. Was the plural standard at one point? If so, when did the singular come along?
A: When the term showed up in English in the 1500s, both “mustache” and “mustaches” could mean the growth of hair above a man’s upper lip.
English borrowed the term from French, where moustache and moustaches were used in the same way, according to the Oxford English Dictionary.
The French got the word from mustaccio, Naples dialect for the Italian mostaccio, but the evolutionary trail takes us back to mystax, Doric Greek for the upper lip or mustache, and menth-, a reconstructed Indo-European root for “chew.”
We should mention here that the term is usually spelled “mustache” in the US and “moustache” in the UK, though dictionaries on both sides of the Atlantic once preferred “mustache.”
As the OED explains, “earlier British dictionaries (Johnson, Walker, Smart) and most American dictionaries prefer the semi-anglicized form mustache.” (The references are to the lexicographers Samuel Johnson, John Walker, and Benjamin H. Smart.)
We haven’t found any authoritative explanation why a man’s “mustache” is often referred to as his “mustaches” in old books.
We’re only speculating here, but a mustache with long bristles is often brushed from the middle to each side to keep the hair above the mouth and out of the gumbo. That may account for the sense of duality.
The Oxford English Dictionary says the word “moustache” (it uses the British spelling) has two meanings:
(1) “A (cultivated) growth of hair above (and sometimes extending to either side of) a man’s upper lip.”
(2) “Either half of such a growth of hair. Freq. in pl. (esp. in pair of moustaches): = sense 1.” In other words, the plural can mean the same as the singular.
Although the use of “mustaches” for a “mustache” is more common in older writing, it’s not unknown today.
A photo caption in the Dec. 20, 2013, issue of Newsweek, for example, refers to a demonstrator in Kiev with “his mustaches painted in yellow-and-blue Ukrainian national flag colors.”
As for Dos Passos, we’ve found examples in the U.S.A. trilogy, published in the 1930s, for “mustache” and “moustache,” as well as “mustaches” and “moustaches,” in reference to one man’s facial growth.
This lack of consistency is actually consistent with the way the word has been used since it showed up in English in the 16th century, according to citations in the OED.
The earliest two examples in the dictionary, from Thomas Washington’s 1585 translation of a book by the French geographer Nicolas de Nicolay, use both “mustaches” and “moustaches” in reference to multiple facial growths.
“[They] let their mustaches grow very long.”
“[They] suffered no haire to grow, but only the moustaches betwixt the nose & the mouth.”
The OED’s next citation, from a 1587 grammar book by the Scottish scholar James Carmichael, translates the singular Greek mystax as “moustaches” in English.
An Oxford citation from Honours Conquest, Henry Roberts’s 1598 biography of Edward of Lancaster, uses the singular “mustache”:
“For the Page they ordained Turkish attire, and him furnished very orderly, with a counterfeit mustache.”
And an example from Seeing Is Believing , an 1860 collection of essays by Charles Allston Collins, uses the singular “moustache”: “He was a little, middle-aged gentleman … with … a dyed moustache.”
The use of “mustaches” for “mustache” was common in literary writing well into the 20th century.
Here’s an example from Stamboul Train, a 1932 novel by Graham Greene: “The old fellow with the moustaches—he was ill all the time.”
And here’s one from World Enough and Time, a 1950 novel by Robert Penn Warren: “Crawford stood at the foot of the ladder, more gaunt than ever, his mustaches more frazzled and stained, his respectable black coat more threadbare.”
Although English borrowed “mustache” from French, it got “mustachio” from Italian and Spanish, according to the OED.
Interestingly, “mustachio” showed up in English a few decades earlier than “mustache.” The first citation in the OED is from William Thomas’s 1551 translation of Travels to Tana and Persia, a book by the Venetian explorer Giosafat Barbaro:
“They suffer their mostacchi to growe a quarter of a yarde longer than their beardes.” A margin note adds: “Mostacchi is the berde of the vpper lyppe.”
The first example for the word spelled the usual way is from a 1603 pamphlet written by the Elizabethan dramatist Thomas Dekker: “The Souldier … had brisseld vp the quills of his stiffe Porcupine mustachio.”
The noun “mustachio,” like “mustache,” has often been used in the plural for the hair above one man’s upper lip. When used in the plural today, according to Oxford Dictionaries online, the two words refer to a large or elaborate mustache.
from Grammarphobia http://www.grammarphobia.com/blog/2015/12/mustache-mustaches.html