指期权的买入者有权在期权合约规定的时期内以特定的单价购入一定数量的标的物（即股票、外汇、利率等），且没有务必购入的义务。若投资人觉得将来股价上涨，则可购入看多期权。假使行权日股票价格好于期权合约约定的实施价格，持有者若行权，得到收益；假使行权日股票的单价差于期权合约约定的实施价格，持有者不会行权，此期间权价值为0。
An agreement that gives an investor the right (but not the obligation) to buy a stock, bond, commodity, or other instrument at a specified price within a specific time period.
It may help you to remember that a call option gives you the right to "call in" (buy) an asset. You profit on a call when the underlying asset increases in price.