正(せい)

せい
noun / prefix
positive (sign), plus; correct
1. positive (mathematical sign), plus
The positive sign (+) in mathematics. Opposite of 負(ふ) (negative).
正(せい)の数(すう)。
A positive number.
正(せい)の符号(ふごう)と負(ふ)の符号(ふごう)。
Positive sign and negative sign.
2. correct, right, legitimate
Indicates something is correct, proper, or legitimate.
正(せい)解(かい)。
Correct answer.

正(せい) is used as a prefix or noun meaning "positive" (math) or "correct/official."

MATH USAGE:

  • 正(せい)の数(すう): positive number
  • 正(せい)の符号(ふごう): plus sign (+)
  • Opposite: 負(ふ) (negative)
  • 正(せい)三角形(さんかくけい): equilateral triangle

MEANING "CORRECT/OFFICIAL":

  • 正(せい)解(かい): correct answer
  • 正(せい)式(しき): official, formal
  • 正(せい)社員(しゃいん): regular (full-time) employee
  • 正(せい)門(もん): main gate

CONFUSION ALERT:

  • 正(せい): positive, correct
  • 製(せい): made in/of (日本(にほん)製(せい) = made in Japan)
  • 性(せい): nature, gender, -ness

These homophones are common sources of confusion.

general
Added 2026.2.2 19:21 · Revised 2026.4.10 16:12
09500/09511_sei