Liqueur is actually a type of spirit or liquor, which itself is a grain-based, distilled alcoholic beverage. A liqueur is a distilled spirit like vodka or brandy that is sweetened with sugar or syrup, and oftentimes it also contains flavoring agents such as fruit, herbs, and oils.
Distillation is the process of separating alcohol from water via evaporation and condensation. The base alcohol is heated, and certain parts of it are captured. This process purifies and concentrates the remaining alcohol, which will ultimately be the final spirit produced.
Distilled spirits are produced from agricultural raw materials such as grapes, other fruit, sugar-cane, molasses, potatoes, cereals.