call -- (1) an option to buy a specific security at a specified price within a designated period. (2) to demand payment of a loan because of the failure of the borrower to comply with the terms of the loan. (3) to demand payment for stocks or bonds that have been purchased or subscribed. See "put."
another definition...
Call -- 1. A demand for early repayment of an obligation, or for the performance of a specific act under a contract.
2. A demand for the payment of money
3. The act of redeeming a bond earlier than the full term.
4. Short for "Call Option," a contract giving the holder the right to receive from the issuer a specified amount of a security at a specified price on or before a certain date.
5. Short for "Margin Call" - a call by a future or an options exchange, or by a broker to its clients, for additional collateral to that previously posted when the futures, options, or securities were purchased without posting their full value.