First, I want to say that this is in no way to question the way somebody is writing. I'm just curious.

I have noticed that some Japanese people here use parentheses and an equals sign to clarify some word or to "define a variable". Example:

...very difficult to explain grammatically even to Japanese (=日本人).

I am pretty sure that most English speakers (or the part of the internet where I've spent most of my time) don't use the equals sign, so I came to the conclusion that this must be a Japanese thing.

Does this carry some other meaning than using plain parentheses in English? Also, is this used in official texts or is it just an informal way to clarify something?

  • 1
    That's not a very typical usage to me, either. But the way you use brackets with equals in your title is common in English writing too, I guess? Apr 22, 2017 at 14:53
  • @broccoliforest Hmm, I guess I just haven't seen it enough before to notice its usage. I googled around a bit and found some distinct uses for it
    – siikamiika
    Apr 23, 2017 at 1:40

1 Answer 1


It appears that (=...) isn't only used in Japanese. In English, it is used a lot in the same way as in the question's title, to clarify the meaning of something when there can be multiple interpretations. Example from Longman Dictionary of Contemporary English:

make a statement (=say something, especially in public)

In Japanese, you can see it used in the same way as in English in informal contexts:

「あの世(=死後の世界)は無い」は、非科学的 3

And a bit more formally:


However, I did not find English usage of (=...) like here:


(This is not typical use according to a native Japanese speaker, see comments)

The way English scientific papers or similar documents usually define abbreviations is with plain parentheses:

moving stations (STAs) → ...aspects of STA mobility

So, (=...) might be used a bit differently in English and Japanese but they seem to mean mostly the same. (...) and (=...) have a similar meaning, but (=...) is not as flexible as (...) in either language.

  • I'll leave this here and if nobody objects, I'll eventually accept it
    – siikamiika
    Apr 23, 2017 at 2:10
  • My impression is that it's more like paraphrasing or showing other names referring to the same thing. books.google.co.jp/… Apr 23, 2017 at 3:53
  • @broccoliforest So you would consider the last one abnormal use? "NP" (= noun phrase) from your link works the other way, paraphrasing "NP" instead of telling that "from now on, we will refer to noun phrases with 'NP'". I think that all the other examples I have in this answer are also just to make it clear what a certain word or expression means
    – siikamiika
    Apr 23, 2017 at 4:10
  • Or if you mean what I say after the last quote, I mean this: imgur.com/a/7oFk1
    – siikamiika
    Apr 23, 2017 at 5:13
  • 1
    I usually take the signs representing "which is what we've discussed under the name of" or "which is we previously (or commonly) know as", so in some sense it could be seen as a subcategory of plain parentheses. In your last one, the writer use them extensively for abbreviation, and I don't call it "typical" use. Apr 23, 2017 at 21:30

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