A digestif is usually small and alcoholic beverage drunk at the end of a meal, most commonly dinner. Digestif comes from the French language, although it's fairly common throughout Southern European countries. Some believe that such digestifs aid digestion, as the name might suggest. A digestif generally will have a higher alcohol content.
Digestifs are usually drunk neat and are most often spirits, such as cognac, armagnacs, brandies, grappas, whiskies, herb-flavored liqueurs, port, sherry, madeira, etc.