sigma

Everyday

1. The eighteenth letter of the Greek alphabet, written Σ (capital) and σ or ς (small). tree →
2. (maths) The capital Σ means "add up all of these" (the sum); small σ is used in statistics for standard deviation (how spread out numbers are). tree →
3. (slang, internet) Used by some young people to mean "cool", "independent" or "the best", as in "sigma male"; often a joke or meme. tree →

In the lessons

In maths, Σ appears in sums: Σ of 1 to 4 means 1 + 2 + 3 + 4 = 10. In science, Greek letters name many things. In playground and internet slang, "sigma" is a meme word for someone who goes their own way; teachers and parents often find it silly. Phrases: sigma notation, sigma male (slang), "that's so sigma" (slang).

Examples

• Σ is the Greek capital letter sigma. tree →
• In maths, Σ means "add them all up". tree →
• The sum Σ from 1 to 5 equals 15. tree →
• "He didn't care what anyone thought — so sigma," joked my brother. tree →
• Small sigma σ is used to show spread in statistics. tree →
• In Greek, sigma makes an "s" sound. tree →

Note

Sounds like "SIG-muh". Greek sigma = English "s". The slang meaning comes from online videos; using it seriously can sound silly, and "sigma male" ideas are not science.