In number theory, σ is included in various divisor functions, especially the sigma function or sum-of-divisors function. In applied mathematics, σ (T) denotes the spectrum of a linear map T.

The small letter sigma (σ) is used to represent standard deviation in math and statistics. It is also used to show syllable in linguistic, a shielding constant in chemistry and sum of divisors in math.

Learn what the sigma symbol means in math and science. Covers uppercase Σ for summation notation, lowercase σ for standard deviation, Riemann sums, z-scores, and how to type sigma.

Learn about the Greek letter Sigma (σ), its pronunciation, usage examples, and common applications in mathematics, science, and engineering.

The Greek letter σ (sigma) is used in statistics to represent the standard deviation of a population. It also has various uses in other areas of math and science.

I love Sigma, it is fun to use, and can do many clever things. So means to sum things up ... Sum whatever is after the Sigma:

Apr 13, 2025 · Letter Σ • (S) (uppercase, nonfinal lowercase σ, final lowercase ς) The letter sigma (σίγμα), the 18th letter of the ancient Greek alphabet.