Starters are specially prepared dishes that are eaten before the main course. Appetizer together with some aperitif, which are in general alcoholic drinks, suppose to stimulate the appetite.
There are hot and cold appetizers that should be light and not too filling to stimulate your palate and keep you hungry. Often a small salad or toast with meat or fish, but also terrines and pies are served.
Soups represent a separate course both in the classic menu, but in the broader sense is often referred to as an appetizer.
The importance of appetizers is different in international kitchens. In French cuisine, there is a mostly cold hors-d’oeuvre and in several Italian antipasti. Appetizers in Spain ( tapas ) and Turkey ( mezze ) can be cold and hot.