Last week I saw the word 閾値 and when looking it up in Gjiten I see two pronunciations, both marked as "popular":

  • 閾値 (いきち) (n) threshold (amount, dose, etc.); (P);
  • 閾値 (しきいち) (n) threshold (amount, dose, etc.); (P);

Which one should I use?
In the context of professional discussion with colleagues and clients, if that matters.

  • 3
    From my personal experience, I hear both pronunciations in technical discussions and I do not think that there is any difference. Jun 1, 2011 at 2:48
  • 1
    +1 Wow, I can't believe I didn't know that word.
    – makdad
    Jun 1, 2011 at 2:53
  • Related?: japanese.stackexchange.com/q/3287/542
    – Flaw
    Jan 9, 2012 at 14:45

4 Answers 4


(thanks to Ito's comment who pointed me in the right direction)

The characters 閾値 should read いきち as per their original pronunciation and is used as is by major dictionary Daijirin.

しきいち is widely used because it's very close to the other word "敷居" (しきい) which also means threshold.

Pronouncing しきい値 is thus grammatically considered a mistake although widely used.

Key sentences:



sources: http://e-words.jp/w/E996BEE580A4.html http://d.hatena.ne.jp/keyword/%A4%B7%A4%AD%A4%A4%C3%CD

  • 2
    (1) This is a reasonable guess, but note the phrase “と思われる” (which means “I think”) in the article. It is not backed up with any source. Strictly speaking, this description should be either improved or deleted according to Wikipedia’s policy which requires verifiable sources. (2) At least the Wikipedia article does not state that the pronunciation しきいち came into use to avoid confusion with other words. Jun 1, 2011 at 3:13
  • This concerns the second sentence in the paragraph. (about the WW2 thing). There's no question about the conventional use being しきいち though.
    – repecmps
    Jun 1, 2011 at 3:16
  • As I said, the Wikipedia article you linked to does not state that the pronunciation しきいち came into use to avoid confusion with other words. “「閾」の字は日本人になじみが薄く、第二次大戦後、当用漢字外とされたため、字義である「敷居(しきい)」の語を当てたものと思われる。” means “the letter 閾 was not included in toyo-kanji after WWII because many Japanese people were not familiar with this letter, and I think that the letter 閾 was pronounced by replacing it with the word 敷居 (しきい) which was the meaning of the letter 閾.” Jun 1, 2011 at 3:25
  • thanks, I edited the answer with better sources. Please take a look and feel free to correct.
    – repecmps
    Jun 1, 2011 at 3:37
  • You still claim the same thing and the same question still remains: where did you get the idea that the pronunciation しきいち is used “to avoid confusion with other words”? I checked the two additional links you provided, but they do not state it either. I am not saying that this reason is incorrect; I do not know if it is true or not. But I am pointing this out to you because you may have written it out of misunderstanding of some of the sources. Jun 1, 2011 at 3:57

Which one should I use?

If you talk to a medical doctor, a psychologist, a biologist or a specialist educated in a field related to medicine and life sciences, I think you should use いきち. If you talk to an engineer, a natural scientist, a computer scientist, or a specialist educated in science and engineering, I think しきいち is more common. Those are their customs.

Wikipedia says "生理学や心理学では「閾値」が、物理学や工学では「しきい値」が、学術用語として定着している。" http://ja.wikipedia.org/wiki/%E3%81%97%E3%81%8D%E3%81%84%E5%80%A4 slashdot.jp/journal/127124/%E9%96%BE%E5%80%A4


I can't say I really know, but the koujien definition for しきいち just refers to the いきち entry, so perhaps the latter is more common or correct?

  • not necessarily; there are certain words which may indicate it is a 訛 of another entry, and the 訛 form might be more common (though not necessarily correct).
    – syockit
    Jun 1, 2011 at 23:28

しきいち is the 湯桶読み (combination of 訓-Yomi & 音-Yomi, which is rare) of いきち (音-Yomi only) according to kotobank.

  • しきい + チ (訓読み + 音読み)
  • イキ + チ (音読み + 音読み)

They shouldn't have any meaning/usage different, but I heard しきいち more often though.

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