Sigma

Greek Letter Sigma (Σίγμα - Σ)

The letter "s" came from the Semitic alphabet, where it was once shaped like latin "W". (The Hebrew "shin", familiar to most people from Jewish religious objects, is the same letter.) The letter was turned to make the classical Greek "sigma". The Greek "sigma" in turn was altered slightly as latin "s". At the end of a word, lower-case sigma is written as latin lower-case "s".

"Σ" Letter in mathematics and in science

Σ represents:

• the summation operator.

σ represents:

• the divisor function in number theory
• the population standard deviation or spread in probability and statistics
• a type of covalent bond in Chemistry (sigma bond)
• the selection operator in Relational algebra
• stress
• electrical conductivity
• areal density
• nuclear cross section
• uncertainty

Greek words with "σ"

ιστορία, σταυρός