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Should We Think ‘Outside’ or ‘Outside of’ the Box?

Should we think ‘outside’ or “outside of” the box?
Should we think ‘outside’ or “outside of” the box?
Should We Think ‘Outside’ or 'Outside of' the Box?
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Hello! This week on Ask a Teacher, we answer a question about the adverb “outside” from Philip in China.



Could you please tell me the difference between outside of and outside? … Please tell me which is better,

We should think outside the box.

We should think outside of the box.

Philip, China.


Dear Philip,

Thank you for writing to us. “Outside” can have one of four uses in English, as a noun, adjective, adverb, or preposition. It is not surprising that you found it hard to understand. Your question brings up an interesting dispute between grammar experts in the United States and Britain. The Oxford English Dictionary says that “outside” in phrases like “outside of the box” is an adverb. It changes the meaning of the verb, in this case, “think.” Together with the preposition “of” it becomes a two-word preposition. Here are other examples of such two-word prepositions:

A baby bird flew out of the nest.

He was never close to his sister.

Your example uses “outside of” or “outside” to talk about the space the subject occupies. You can use either “outside” alone or with “of” in that sense. There is another use where “outside of” means “apart from” or “besides.” Here are examples of that use:

Outside of their later songs, I do not enjoy the Beatles’ music.

I cannot think of a time outside of high school when I wore a tie.

The Merriam-Webster Learners Dictionary says “outside of” is a North American use. Another British dictionary, the online Oxford Dictionaries also sees the use of “outside of” to talk about location as “chiefly North American.” But its use in the “apart from” sense is seen as normal for British and American English.

So in British English, you would usually hear,

Think outside the box.

And in American English, you might hear it that way or

Think outside of the box.

What question do you have about American English? Send us an email at

And that’s Ask a Teacher.

I’m Jill Robbins.

Dr. Jill Robbins wrote this lesson for VOA Learning English.


Words in This Story

puzzlev. to be difficult for (someone) to understand

location –n. a place or position

think outside the box – (expression) If you think outside the box, your thoughts are not limited or controlled by rules or tradition, and you have ideas that are creative and unusual.

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