Swaps are a type of derivative. They are exchanged outside of the stock market as OTC-trades.
There are different types of swaps - including credit default swaps, dividend-swaps, total return swaps, asset swaps and interest rate swaps.
What all swaps have in common is that future liabilities and assets are exchanged between two parties, or «swapped». A swap can be used to protect investments or to minimize financial risk.
Unlike futures, forwards and other investment vehicles which operate within a fixed time frame, swaps do not have fixed exchange dates. It’s also worth noting that a swap is never actually «physically» paid out.