Though it’s no longer official,* over is widely considered incorrect when used in front of a number; the correct term is more than. You’ll have learned more than you need to know once you’ve read over this lesson.
More than means "in excess of" when followed by a number or an adverb of quantity.
I have more than 10 pairs of black shoes.
More than 50% of the citizens voted this year.
They have more than enough money to live comfortably.
More than can also be split by a noun or clause to make a comparison:
I have more shoes than my sister does.
50% more people voted this year than last year.
They have more money than sense.
Over can be a preposition or an adverb and has numerous meanings and uses, but only one matters for the purposes of this lesson.
American Heritage Dictionary: definition prep. 9
More than in degree, quantity, or extent: over ten miles; over a thousand dollars.
Cambridge Dictionaries Online: definition preposition A2
more than: Most of the carpets cost/are over £100.
Collins English Dictionary: definition preposition 8
more than => over a century ago
Dictionary.com: definition preposition 13
in excess of; more than: over a mile; not over five dollars.
Merriam-Webster Dictionary: definition preposition 3a
more than <cost over $5>
Oxford Dictionary: definition preposition 3
Higher or more than (a specified number or quantity): ‘over 40 degrees C’
As you can see, over meaning more than is permissable according to many dictionaries, both American and British, which makes this "error" seem pretty arbitrary.
Interestingly, when the term is preceded by "just," over has to be used because more than simply doesn’t sound right:
Just over 50% of the class attended the pep rally.
Just more than 50% of the class attended the pep rally.
It cost just over $5.
It cost just more than $5.
The Bottom Line
According to dictionaries and, now, the Associated Press Stylebook, there’s nothing wrong with saying over rather than more than, so it might be time to just get over it – there are more than enough real English errors to be worried about without adding fake ones.
*From 1877, when New York Evening Post editor William Cullen Bryant proclaimed in Index Expurgatorius that "over" should not be used in front of numbers,** until 2014, the use of "over" to mean "more than" was considered incorrect. The AP Stylebook‘s announcement that this was no longer the case elicited gasps and even anger from journalists, but in a generation or two, saying things like "over 50%" probably won’t even raise an eyebrow.
**Source: "Over." Merriam-Webster’s Dictionary of English Usage. Springfield: Merriam-Webster, Incorporated, 1994.
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