The kanji 原 and 源 seem to often have not only an identical pronunciation, but also a very similar meaning, and I'm having a lot of trouble remembering the spellings of several words:

Using 原:

Using 源:

I'm wondering if there's some shade of meaning that I am missing between these two characters, or maybe if there's some Japanese equivalent to the "i before e except after c" rule that would help me remember which is which. For the most part, it does not seem that the words containing 原 have anything more to do with meadows than the words containing 源.

  • 1
    At the very least, I think 原因 refers to the question 'why' and 起源 refers to the question 'how', even though are an origin or beginning. Perhaps this shade of meaning permeates the rest of the words using the respective kanji. Jan 3, 2017 at 23:00
  • However, any word I can think of right now that means 'first' or 'original' uses 原. I'm aware that my comments may be unhelpful... Jan 3, 2017 at 23:02

1 Answer 1


Putting etymology aside, in modern Japanese...

源 means resource. When one can draw something useful from it, always use ○源. Similarly, a place from which something is (radially) emitted is described using 源.

  • 水源、電源、光源、熱源、財源、音源、動力源、エネルギー源、タンパク源
  • 震源、発生源、汚染源、ノイズ源

原 means cause. When it's the cause for something, use 原. (incidentally English uses a similar-looking suffix -gen)

  • 原因、病原体 (pathogen)、アレルギー原 (allergen)

原 also means primitive or fundamental:

  • 原始、原初、原子、原理、原則、原色

原 also means atomic/nuclear:

  • 原発 (short for 原子力発電所)、原爆 (short for 原子爆弾)

Unfortunately, these are still many difficult cases, especially when the word translates to "origin(al)" or "source". But you can use 原 and 源 interchangeably in some cases.

  • 原型、原作、原料
  • 源泉
  • 起源 / 起原
  • 語源 / 語原
  • 根源 / 根元 / 根原
  • So why is this question upvoted 5 times and the answer is only once? I am sure the answer provides much more insight than the question.
    – KyloRen
    Jan 4, 2017 at 13:58
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    @KyloRen 回答したのはそのコメントの26分前なので…
    – naruto
    Jan 4, 2017 at 14:04
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    @KyloRen Sometimes people don't vote on answers because they don't know enough about the answer themselves to judge whether it's right or wrong. But these same people feel comfortable voting on questions because it doesn't require as much knowledge to say "Hey, that's a good question!" :-) I'm sure this answer will get upvotes, though.
    – user1478
    Jan 4, 2017 at 14:32
  • Thanks, this is very useful. I think together with @JamesEdwards distinguishing between "why" and "how" for 原因 vs. 起源 helps with the "origin" disambiguation - why? Because of the cause. How? Using the resource.
    – Paul
    Jan 4, 2017 at 15:42

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