An option contract has several key elements that define the terms of the contract:

1. **Underlying Asset**: This is the specific security that the option contract is based on. It could be a stock, an index, a commodity, etc.

2. **Type of Option**: This refers to whether the option is a call or a put. A call gives the holder the right to buy the asset, while a put gives the holder the right to sell the asset.

3. **Strike Price**: This is the predetermined price at which the underlying asset can be bought or sold.

4. **Expiration Date**: The date on which the option contract becomes invalid and ceases to exist. 

5. **Option Premium**: This is the price that the option buyer pays to the option seller. It’s determined by factors such as the underlying asset’s price, the strike price, the time remaining until expiration, and the volatility of the underlying asset.

– Reference: [Investopedia: Option Contract](https://www.investopedia.com/terms/o/optioncontract.asp)