sigma
noun
Simple meaning
The symbol Σ, used to indicate summation of a set or series.
Pronunciation
Say it like this:
sigmuhSay the bold part a little louder.
IPA pronunciation (US)
ˈsɪɡmə
This word is pronounced essentially the same in American and British English, so one transcription covers both.
IPA (International Phonetic Alphabet) is a standard way of writing speech sounds.
Definition
Everyday modern meanings first, grouped by part of speech.
noun
mathematics
The symbol Σ, used to indicate summation of a set or series.
The eighteenth letter of the Classical and Modern Greek alphabets (Σ, σ), the twentieth letter of Old and Ancient.
statistics
The symbol σ, used to indicate one standard deviation from the mean, particularly in a normal distribution.
Word Aura™
How this word commonly comes across.
Aura for this meaning
This meaning: The symbol Σ, used to indicate summation of a set or series.
Used this way, sigma is a specialist word that usually carries little praise or criticism of its own. This is a mathematical use: it is defined precisely and belongs to working with figures and calculations rather than to ordinary conversation.
- Emotional tone
- Neutral
- Formality
- Specialist/technical
- Intensity
- Not strongly marked
- How common
- Specialized
- Connotation
- Clinical and technical
- Usage feel
- Technical and specialized
Where it naturally appears
- Mathematics
- Geometry
- Academic writing
- Education/classroom
Usage note
In general conversation this sense usually needs explaining — outside its field, people reach for a plainer word.
Word Aura describes common impressions, not a measurement. Tone changes with sentence, speaker, relationship and situation.
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Dictionary data from Wiktionary via the Free Dictionary API. Simple meanings, combinations and word intelligence are built from verified reference data, no AI is used to load this page.