The Greeks are a set of metrics that determine why, how, and when your option's value will change. Delta is probably the most commonly cited Greek -- but don't think you can become a stellar options trader without learning the ins and outs of theta, too.
Below, you'll find a quick primer on the Greeks. For more in-depth information on each of these metrics, pay a visit to the Option Greeks entry in our Key Option Concepts section.
Beta. A measure of how a stock moves more or less in relation to the movement of a broader market index.
Delta. The percentage of an underlying stock's gain or loss that will translate into the corresponding option's gain or loss.
Gamma. The unit change in the delta of an option for each point change in the price of the underlying stock or index.
Rho. The sensitivity of an option to a change in interest rates.
Theta. The loss in value an option will experience due to the passage of time. As a quantification of time decay, theta is usually expressed on a per-day basis.
Vega. The change in an option's price based on the change in its implied volatility, expressed in dollar terms.