せい 正 Common word JLPT N3 Show 2 collocations 正と反 - thesis and antithesis正と続 - first and second series LinksSentence search for 正Sentence search for せいKanji details for 正Edit in JMdict Noun, No-adjective1. (logical) true; regularNumeric2. 10^40; ten thousand undecillionNoun, No-adjective3. originalAbbreviation, See also 正本 せいほん4. positive; greater than zeroMathematics, See also 負 ふNoun5. thesis (in dialectics)See also 定立, See also 正反合 Discussions Log in to talk about this word.