Usually the phrasal verb look up is used as follows. These example sentences are from the Oxford Advanced Learner's Dictionary.

Can you look up the opening times on the website?

I looked it up in the dictionary.

The objects of the phrasal verb in those above sentences are what are actually needed to be found.

Suddenly, I saw this sentence from an English learning material which is not popular and this sentence was there alone so there is no context I can add here.

Look up the dictionary if you have trouble translating.

As the dictionary in that sentence is not something searched for but something used as an instrumentality to search for something else, I somehow feels the sentence below is more correct.

Look up in the dictionary if you have trouble translating.

I would like to know what is right and wrong. Thank you.

  • @user3169 I feel sorry that I couldn't add a specific context to it. Actually that sentence itself was an example sentence from a book which is not popular nor of a popular publisher. That sentence was standing alone and there was no description nor context involved. But, I edited the post and added this fact. Dec 11, 2018 at 19:00
  • @user3169 I know if I asked a question with more context or explanation about the source it would be much better. I will try to do so. But I thought this was something I felt I really needed to ask. Moreover, at the initial view, this didn't seem to really need any more context as there is if you have trouble translating in the sentence which is showing the context. Dec 11, 2018 at 19:13
  • @user3169 But doesn't it still need the preposition in before the list, just like look up in the opening times? Dec 12, 2018 at 20:26

1 Answer 1


You’re right: “Look it up in the dictionary” would be preferred unless the meaning of the sentence is “Look up the foreign dictionary in the library” or something like that. “Look up the dictionary” gets the meaning across, but it’s sloppy English.

  • 1
    I disagree there is any problem with 'Look up the dictionary'. It uses the imperative mood of the verb (commands) rather than the indicative mood (descriptive statements). 'See this!', 'Do that!, etc., are valid for sentences which have verbs in the imperative mood. This seems no different to those to me. Dec 9, 2018 at 7:51
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    Upon a rethink, I think using 'in' is probably technically better, but issuing an instruction with something like 'Look up the dictionary' is so common I would regard it as an acceptable idiom. Dec 9, 2018 at 8:00
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    @RossMurray Taking another look at it myself, I agree with you: "entry" is an implied object as in, "Look up the dictionary entry."
    – Josh B.
    Dec 10, 2018 at 6:31
  • Thanks, @Josh. I take the view that being here would not be fun for us if it was easy. :-) Dec 10, 2018 at 6:46
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    @RossMurray A mod is going to shut us down, haha. I'd argue that by expressing a condition contrary to fact ("easy") you're inherently using the subjunctive mood and ipso facto must follow its rules. Just like I can't say "Is that a dog" and punctuate it with a period instead of a question mark.
    – Josh B.
    Dec 10, 2018 at 7:10

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