sigma

[sig-muh] /ˈsɪg mə/
noun
1.
the 18th letter of the Greek alphabet: Σ, σ, ς.
2.
the consonant sound represented by this letter.
Origin
1600-10; < Latin < Greek sígma
Examples from the web for sigma
  • By definition, three sigma events are not supposed to come in battalions.
  • If we're on the topic of alternatives how about some form of six-sigma normalization of the prices of goods and wages.
  • sigma receptors are effected by cocaine, as cocaine functions as a sigma ligand agonist.
British Dictionary definitions for sigma

sigma

/ˈsɪɡmə/
noun
1.
the 18th letter in the Greek alphabet (Σ, σ, or, when final, ς), a consonant, transliterated as S
2.
(maths) the symbol Σ, indicating summation of the numbers or quantities indicated
Word Origin
Greek, of Semitic origin; related to Hebrew samekh
Word Origin and History for sigma

18th letter of the Greek alphabet, corresponding to Latin S, a metathesis of Hebrew samekh. In uncial writing, shaped like an S or a C.

sigma in Medicine

sigma sig·ma (sĭg'mə)
n.

Symbol ς The 18th letter of the Greek alphabet.

sigma in Science
sigma
  (sĭg'mə)   
A sigma baryon.
sigma in Technology

A scientific visual programming environment from NASA.
(https://fi-www.arc.nasa.gov/fia/projects/sigma/).