係数(けいすう)

けいすう
noun
coefficient; factor
1. coefficient; factor; modulus
A numerical or constant factor in a mathematical expression, physics formula, or engineering calculation. In algebra, the number multiplying a variable (the 3 in 3x). In physics and engineering, often translated "coefficient" or "modulus" depending on the quantity (friction, expansion, elasticity, etc.).
摩擦(まさつ)係数(けいすう)を計算(けいさん)する。
To calculate the coefficient of friction.
方程式(ほうていしき)の係数(けいすう)を揃(そろ)えて解(と)く。
Solve by lining up the coefficients of the equation.
温度(おんど)が上(あ)がると、材料(ざいりょう)の熱膨張(ねつぼうちょう)係数(けいすう)に応(おう)じて長(なが)さが変化(へんか)する。
As the temperature rises, the length changes according to the material's coefficient of thermal expansion.

Compound of 係(けい) ("to relate to, to involve") + 数(すう) ("number"). A technical term used across mathematics, physics, statistics, and engineering. The specific English translation varies by context — "coefficient," "factor," or "modulus."

COMMON COMPOUNDS:

  • 摩擦(まさつ)係数(けいすう): coefficient of friction
  • 熱膨張(ねつぼうちょう)係数(けいすう): coefficient of thermal expansion
  • 相関(そうかん)係数(けいすう): correlation coefficient
  • 弾性(だんせい)係数(けいすう): modulus of elasticity
  • 抵抗(ていこう)係数(けいすう): drag/resistance coefficient

SIMILAR WORDS:

  • 定数(ていすう): constant — a fixed value; broader than 係数(けいすう), not tied to a variable
  • 変数(へんすう): variable — the opposite role; 係数(けいすう) multiplies a 変数(へんすう)
general
Added 2026.5.11 16:07
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