How to say "conjunction" in Japanese

• 連言れんげん
  nounThe conjunction of logic, joining two statements with 'and' so both must be true. This is the standard logical term, used in philosophy and formal logic rather than everyday language.
• 接続詞せつぞくしJLPT N1approx.
  nounThe grammatical conjunction — a word like 'and', 'but', or 'because' that links phrases and clauses. This is the word you want for the parts-of-speech sense of 'conjunction'.
  関係かんけい代だい名詞めいしは「接続詞せつぞくし+代名詞だいめいし」のはたらきをしています。↗

  Relative pronouns perform as 'conjunction + pronoun'.
• 論理積結合ろんりせきけつごう
  nounA technical term for conjunction as the AND operation, combining conditions so all must hold. Use it only in logic or computer-science contexts; it is not a general word for 'conjunction'.
• 合接ごうせつ
  nounAn obscure term glossed 'conjunction; joint'. Its basic sense is joining or coming together, and it is seldom the word you want for 'conjunction'; learners will rarely need it.
• 論理積ろんりせき
  nounThe logical product or AND operation, also glossed 'conjunction' and 'intersection'. It belongs to logic and computing, where it denotes the operation true only when all inputs are true.

For grammar use 接続詞; for the logical sense 連言 is the usual term, while 論理積 and 論理積結合 belong to logic and computing; 合接 is rare and mostly means joint.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 連言れんげんconjunction
• 接続詞せつぞくしconjunction
• 論理積結合ろんりせきけつごうconjunction
• 合接ごうせつconjunction
• 論理積ろんりせきlogical product
• 接続せつぞくconjunction
• 会合かいごうconjunction
• 合ごうconjunction