Sure. An option is a contract which gives you the right to buy a fixed amount of an underlying asset at a predetermined price before a certain date.

For instance, I could buy a "call" option on Apple which expires on December 15th and has a strike price of $150. This would give me the option, but not the obligation, to buy 100 shares of apple stock on or before that date.

If I think that apple will be trading at more than $150 a share, then that contract would be valuable and I would pay some premium for it. If I end up being wrong and Apple is cheaper than $150 a share, my option will expire worthless.

The same can go in the other direction, but it works by borrowing and selling shares first, and is called a put option. You can also choose to sell these options if you own the underlying and want to hedge or generate yield, or even sell them naked if you want to go way out on the risk curve.

But basically all you need to know is that it is an option to act on an asset at a fixed price before a certain date.