The limit on the number of contracts which a holder can exercise in a fixed period of time. Set by the appropriate option exchange, it is designed to prevent an investor or group of investors from "cornering" the market in a stock.
See Also:
Exercise: Implementing an option's right to buy or sell the underlying security. In the case of a call, the option owner buys the underlying stock. In the case of a put, the option owner sells the underlying stock.