當且僅當

Chinese

		to act as; represent; equal to act as; represent; equal; should; fitting; suitable; adequate; proper; replace; to be; to hold a position; manage; withstand; when; during; ought; match equally; same; obstruct; just at (a time or place); on the spot; right; just at	further; moreover	barely; only; merely	to act as; represent; equal to act as; represent; equal; should; fitting; suitable; adequate; proper; replace; to be; to hold a position; manage; withstand; when; during; ought; match equally; same; obstruct; just at (a time or place); on the spot; right; just at
trad. (當且僅當)		當	且	僅	當
simp. (当且仅当)		当	且	仅	当
Literally: “when and only when”.

Pronunciation

• Mandarin

  (Pinyin): dāngqiějǐndāng

  (Zhuyin): ㄉㄤ ㄑㄧㄝˇ ㄐㄧㄣˇ ㄉㄤ

• Cantonese (Jyutping): dong¹ ce² gan² dong¹

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• Mandarin
  • (Standard Chinese)⁺
    • Hanyu Pinyin: dāngqiějǐndāng [Phonetic: dāngqiéjǐndāng]
    • Zhuyin: ㄉㄤ ㄑㄧㄝˇ ㄐㄧㄣˇ ㄉㄤ
    • Tongyong Pinyin: dangciějǐndang
    • Wade–Giles: tang¹-chʻieh³-chin³-tang¹
    • Yale: dāng-chyě-jǐn-dāng
    • Gwoyeu Romatzyh: dangchieejiindang
    • Palladius: данцецзиньдан (danceczinʹdan)
    • Sinological IPA ^(key): /tɑŋ⁵⁵ t͡ɕʰi̯ɛ²¹⁴⁻³⁵ t͡ɕin²¹⁴⁻²¹ tɑŋ⁵⁵/
• Cantonese
  • (Standard Cantonese, Guangzhou–Hong Kong)⁺
    • Jyutping: dong¹ ce² gan² dong¹
    • Yale: dōng ché gán dōng
    • Cantonese Pinyin: dong¹ tse² gan² dong¹
    • Guangdong Romanization: dong¹ cé² gen² dong¹
    • Sinological IPA ^(key): /tɔːŋ⁵⁵ t͡sʰɛː³⁵ kɐn³⁵ tɔːŋ⁵⁵/

Conjunction

當且僅當

1. (Mainland China, mathematics, logic) if and only if

Synonyms

• 若且唯若 (ruòqiěwéiruò)