Strike Price
The price at which the holder of an options can can buy (in the case of a call) or sell (in the case of a put) the underlying security when the option is exercised. Also called the exercise price. The moneyness of an option depends on its striking price.
Striking Price Intervals
The strike price intervals vary depending on the market price and asset type of the underlying. For lower priced stocks (usually $25 or less), intervals are at 2.5 points. Higher priced stocks have strike price intervals of 5 point (or 10 points for very expensive stocks priced at $200 or more). Index options typically have strike price intervals of 5 or 10 points while futures options generally have strike intervals of around one or two points.