Its odd that someone called greeks wouldn't know what sigma means 
Sigma is the symbol (and word) used for standard deviation. Google a bit for a statistics primer if needed.

Sigma is the symbol (and word) used for standard deviation. Google a bit for a statistics primer if needed.
Quote from greeks:
I started seeing this Sigma thing but have not idea what it's. Would someone please explain it?
Thnaks,
Tom