The seller of a call option may be obligated to fulfill the terms of the contract and sell the underlying stock at a specific price in exchange for the premium they have received. (us.etrade.com)
Options and futures are generally interchangeable terms, and represent a contract to buy a specific asset at a specific price at a future date. (entrepreneur.com)
A client's order to buy or sell securities at a specific price or better. (hsbc.ca)