sigma

/ˈsɪɡmə/
noun
  1. The 18th letter of the Greek alphabet (Σ, σ, ς).
    • The word 'psychology' starts with the Greek letter psi, not sigma.
    • The Greek letter sigma looks like an 'E' but is pronounced 'sig-muh'.
    • In math class, we use sigma to represent the sum of a series.
  2. A symbol (Σ) used in mathematics to denote summation.
    • The formula uses sigma to show the total of all numbers from 1 to 10.
    • The teacher explained how to read sigma expressions in algebra.
    • You can write the sum of a sequence using the sigma notation.
  3. A statistical measure of standard deviation.
    • The engineer calculated the sigma to check the consistency of the product.
    • A low sigma value means the data points are close to the average.
    • The quality control team uses six sigma methods to reduce errors.
What does "sigma" mean? | whatsthatwordmean | whatsthatwordmean