A pip is the smallest possible movement that an asset can make, whether it’s up or down. If the price of EUR/USD is 1.33610 and it changes to 1.33611, it means that it’s moved by 1 pip. However, not all assets have 5 decimals. For example USD/JPY usually has 2 decimals, so a movement of 0.01 would mean a change by1 pip.
In the case of binary options, all we need to know is that if the price, in the expiration time, is higher or lower by one single pip that you’ve predicted then the trade is considered successful or in-the-money. That’s all it takes for your trade to be profitable