sigma

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/ˈsɪɡmə/
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A Greek alphabet letter used as a symbol in science and statistics, and in modern slang a self-reliant outsider archetype.
Practice using this word in conversation

Examples

  • The word sigma names a Greek letter, not the Latin letter S.
  • The lowercase sigma is written as σ.
  • He was described online as a sigma because he avoids status games.
  • In the Greek alphabet, sigma follows rho.
  • Engineers tracked sigma to measure process variation.

Similar words

independent
spread
Greek S
dispersion
nonconformist
Greek letter sigma
standard deviation
maverick
outsider
sigma value

Meanings

Greek letter

noun
language
neutral
The eighteenth letter of the Greek alphabet, written as σ in lowercase and Σ in uppercase.

Usage

Use sigma for the Greek letter or its symbol, especially in language, mathematics, and science.

Examples

  • The lowercase sigma is written as σ.
  • Uppercase Sigma appears as Σ in Greek text.
  • In the Greek alphabet, sigma follows rho.
  • Ancient inscriptions used forms of sigma that changed over time.
  • The word sigma names a Greek letter, not the Latin letter S.
  • Final sigma has a special lowercase form in Greek.
  • Many scientific symbols are based on sigma.

Common mistakes

Writing it as ordinary S confuses the Greek letter with the Latin alphabet.
IncorrectCorrect
Sigma is just the English letter S. Sigma is a Greek letter related to, but distinct from, the Latin S.
The lowercase sigma is Σ. The lowercase sigma is σ, while uppercase sigma is Σ.
Every Greek sigma looks the same in lowercase. Greek has σ in most positions and ς at the end of a word.
Use sigma to name any Greek letter. Use sigma only for the Greek letter σ or Σ.

Similar words

Greek letter sigma
sigma letter
sigma symbol
Greek S

Standard deviation

noun
statistics
technical
A symbol and informal name for standard deviation, especially the population standard deviation in statistics.

Usage

Use sigma when the context is statistical variation, and distinguish it from the uppercase summation sign.

Examples

  • The sigma of the sample was 2.4.
  • A larger sigma shows that the data are more spread out.
  • The formula uses sigma for the population standard deviation.
  • Engineers tracked sigma to measure process variation.
  • The report lists the mean and sigma for each group.
  • A low sigma can signal more consistent measurements.
  • The model assumes a sigma of one.

Common mistakes

Using sigma for the mean or for a total gives the wrong statistical quantity.
IncorrectCorrect
The sigma is the average of the data. The sigma is the standard deviation, not the average.
A bigger sigma means the values are closer together. A bigger sigma means the values are more spread out.
Use sigma to add all the numbers. Use uppercase Σ for summation and sigma for standard deviation when that is the convention.
Variance and sigma are the same value. Variance is sigma squared when sigma is the standard deviation.

Similar words

standard deviation
population standard deviation
dispersion
spread
sigma value

Independent person

noun
culture
slang
A slang term for a self-reliant person, often a man, who is portrayed as succeeding outside traditional social hierarchies.

Usage

Use sigma for the internet archetype of independence, and keep the slang tone clear.

Examples

  • He was described online as a sigma because he avoids status games.
  • The film presents its hero as a quiet sigma who works alone.
  • Social media often treats the sigma as an outsider success story.
  • Calling someone a sigma usually suggests independence, not leadership.
  • The joke compared the loner character to a sigma.
  • Fans read the protagonist as a sigma figure.
  • The meme praised the sigma for ignoring the crowd.

Common mistakes

Treating it as a formal personality type overstates a loose internet label.
IncorrectCorrect
Sigma is a proven personality diagnosis. Sigma is slang for an independent social archetype.
A sigma is the same as an alpha. A sigma is framed as outside the hierarchy, while an alpha is framed as dominant within it.
Every quiet person is a sigma. A sigma is described as self-reliant and independent, not merely quiet.
Sigma always means lonely or antisocial. Sigma emphasizes independence, not necessarily loneliness or hostility.

Similar words

lone wolf
independent
nonconformist
maverick
outsider

Usage

Use context to separate the Greek-letter and statistics uses from the newer slang sense for an independent person.

Common mistakes

Calling it a formal personality type or confusing σ with uppercase Σ can make the intended sense unclear.

Etymology

From Latin sigma, from Greek sigma, the name of the Greek letter.

FAQ

What does sigma mean?

Sigma can mean the Greek letter σ or Σ, a symbol for standard deviation, or slang for an independent person.

What does sigma mean as slang?

As slang, sigma describes a self-reliant person portrayed as succeeding outside traditional social hierarchies.

Is sigma the same as alpha?

No. Alpha is framed as dominant inside a hierarchy, while sigma is framed as independent of that hierarchy.

What is sigma in statistics?

In statistics, sigma often means standard deviation, especially the population standard deviation.

What is sigma in the Greek alphabet?

Sigma is the eighteenth Greek letter, written σ in lowercase and Σ in uppercase.

Is sigma a formal personality type?

No. The slang sense is an internet archetype, not a formal psychological category.

Where does sigma come from?

The word comes through Latin from Greek sigma, the name of the Greek letter.

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