**Sigma, **

### Definition of Sigma:

Standard deviation.

Mathematical sum.

See Six Sigma.

The eighteenth letter of the Greek alphabet (Σ, σ), transliterated as ‘s.’.

The eighteenth star in a constellation.

In mathematics, the Greek symbol sigma represents a summation operator.

Relating to or denoting an electron or orbital with zero angular momentum around an internuclear axis.

### How to use Sigma in a sentence?

- These conical intersections are fundamentally different from the ‘H-vinyl’ structures found in simple alkenes because they involve the interaction of four sigma electrons, as opposed to two pi electrons and two sigma electrons.
- He coined this latter term and employed the Greek letter lower case sigma to denote its population parameter.
- Sigma Octantis.

Meaning of Sigma & Sigma Definition