A CFD spread is the difference between the price you can buy a CFD or sell a CFD. The two prices are sometimes referred to as the bid and ask. The spread can also be referred to as the bid-ask spread.
For example, if you are trading the EURUSD and the current price is 1.1210, and there is a two pip spread. The price you will be able to buy the EURUSD CFD at is 1.1211, and the price you will be able to sell it at is 1.1209