Q: I would say a house costs 3 million, but my mother-in-law (an ex-teacher of English) insists that it should be 3 millions. Who is right, and why?
A: You’re right. We’ll leave it to you to break this to your mother-in-law.
The term “million” (like “thousand” and “hundred”) is normally singular when preceded by a quantifier like “four” or “several.”
Examples: “Four million homes are affected, but only two million have been evacuated.”
We can understand your mother-in-law’s reasoning here. She regards “million” as a noun in “he paid 3 million,” and reasons that a noun modified by a plural number should be plural: “he paid 3 millions.”
But nouns that stand for numbers don’t act the same as ordinary nouns.
The Oxford English Dictionary says that the noun “million” is an “unmarked” plural—it has no plural ending—when “modified by a numeral adjective or (freq.) a quantifier.”
Here are some of the examples given in the OED, along with their dates:
“v mylȝon off fynest gold” (“5 million of finest gold,” c1478);
“a thousand milion, Rejoysing” (c1530);
“between four and five million in the kingdom” (1780);
“a thousand million of pounds sterling” (1856);
“brave nation of forty million” (1915);
”six million of his fellow Jews” (1972);
“several million more” (1975);
and “sold three million of them” (1991).
In this respect, the OED says, “million” can be compared with “dozen” and “hundred.”
Fowler’s Modern English Usage (rev. 3rd ed.) has a discussion of “million,” and provides a few general rules about the singular and plural uses:
“When modified by a preceding quantitative word (a numeral, many, several, etc.) and followed immediately by a noun, million is unchanged in form (two million people, several million pounds).”
And if no noun follows? Fowler’s says, “Million (not millions) is used in the type Among the eight million are a few hundred to whom this does not apply.”
The usage guide also says that “a million” is “sometimes used elliptically” to mean “a million pounds” or “a million dollars.” All that’s deleted is the currency.
So while Fowler’s doesn’t say so directly, it’s reasonable to assume that “3 million” (not “3 millions”) would be short for “3 million pounds” or “3 million dollars.”
When the currency symbol is used instead, the word is always singular, as in “£3 million” or “$3 million.”
When an “of” phrase follows, Fowler’s says, “the plural is normally used (many millions of votes were lost),” although idiom allows the singular in phrases like “a few million of them.”
As for the word’s history, the OED notes that “million,” meaning “a thousand times a thousand,” first appeared in written English in the 14th century as both noun and adjective.
English borrowed “million” from Old French, but its ultimate source is the classical Latin mille (thousand,) which is also the source of the English “millennium” (a thousand years) and “mile” (etymologically it means a thousand paces).
The OED’s earliest recorded use of the noun is from William Langland’s long poem Piers Plowman, composed some time before 1376): “Manye mylions mo of men & of wommen.”
In older writing, according to Oxford, the term was often seen in the plural when modified by a number: “200 Millions” (c1595); “near eighty millions Sterling” (1790); “This four millions was taken account of” (1902).
These days, however, the singular is the common idiomatic usage: “he rakes in 20 million a year.”
The earliest adjectival use in the OED is from a manuscript of The Visions of St. Paul that dates from around 1390: “Þen kneled Poul and Mihel And a Milioun Angeles.” (“Then kneeled Paul and Michael and a million angels.”)
Like Fowler’s, the OED notes that the noun “million” is used elliptically to mean “a million coins or units of money of account of some understood value.”
When money is the subject, the plural “millions” is seen more often when there’s no number: “they have millions in the bank” … “she made her millions in the market.”