Using parentheses (=round brackets) with equals sign

Question

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?

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:

窃盗(=万引)撲滅市川駅周辺店舗連絡協議会

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

インパクトファクター(=IF)の概要、誤用に続き、今号ではIFとその他の引用指標の活用法についてご説明します。

(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:

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.