Definition of 'Option'
A financial derivative that represents a contract sold by one party (option writer) to another party (option holder). The contract offers the buyer the right, but not the obligation, to buy (call) or sell (put) a security or other financial asset at an agreed-upon price (the strike price) during a certain period of time or on a specific date (exercise date).
Call options give the option to buy at certain price, so the buyer would want the stock to go up.
Put options give the option to sell at a certain price, so the buyer would want the stock to go down.
Investopedia explains 'Option'
Options are extremely versatile securities that can be used in many different ways. Traders use options to speculate, which is a relatively risky practice, while hedgers use options to reduce the risk of holding an asset.
In terms of speculation, option buyers and writers have conflicting views regarding the outlook on the performance of an underlying security.
For example, because the option writer will need to provide the underlying shares in the event that the stock's market price will exceed the strike, an option writer that sells a call option believes that the underlying stock's price will drop relative to the option's strike price during the life of the option, as that is how he or she will reap maximum profit.
This is exactly the opposite outlook of the option buyer. The buyer believes that the underlying stock will rise, because if this happens, the buyer will be able to acquire the stock for a lower price and then sell it for a profit.
Want to know more about options? Read: Forget The Stop, You've Got Options and Getting Acquainted With Options Trading.