To say appetizer is to say a small bite of something that awakens a palate. Every nation has its appetizers and the Italian Antipasto is a classic on many tables. Frequently these savories are encased in doughs, such as pierogi, or wrapped or baked in crusts, filo dough being a good example. Primarily we love the doughy feeling, but the small mouthful is easy to eat at a party. These all make wonderful main courses as well and the idea of the appetizer moves further away from us.
How do we classify a vegetable mix wrapped in dough that turns around and shows up containing a meat or fish mixture. SW hat might be a great side dish is also a wonderful appetizer at a party. Many of these are unclassifiable, all of them are fun. Some of these are labor intensive, appropriate for the elegant holiday meal, some thrown together for speedy serving.