Simple syrup is a combination of sugar and water that has been heated enough for the sugar to melt and then chilled before using. If you are going to start making your own cocktails, I advise making a batch to keep on hand. One half cup sugar and one half cup water until water boils and you can no longer see the sugar crystals; then cool and keep in fridge. It keeps a long time and is easier than making a small amount each time you craft a cocktail.