Capital gains
Profit from selling above your cost.
A capital gain is the profit you make when you sell an investment for more than you paid. Selling for less is a capital loss.
Realized vs unrealized
A gain on paper is unrealized; it becomes realized, and usually taxable, only when you sell. Long-term investors who rarely sell can let gains build for decades before paying tax.
ExampleBuy shares for $1,000 and sell them for $1,500, and you have a $500 capital gain.