HORS D'OEUVRES

If there is an extended period between when guests arrive and when the meal is served (for example during a cocktail hour), these might also serve the purpose of sustaining guests during the wait, in the same way that aperitifs are served as a drink before meals. Hors d'oeuvre are sometimes served with no meal afterward. This is the case with many reception and cocktail party events.
Hors d'oeuvre may be served at the table, as a part of the sit-down meal, or they may be served before sitting at the table. Hors d'oeuvre prior to a meal are either stationary or passed. Stationary hors d'oeuvre are also referred to as "table hors d'oeuvre". Passed hors d'oeuvre are also referred to as "butler-style" or "butlered" hors d'oeuvre.
Though any food served prior to the main course is technically an hors d'oeuvre, the phrase is generally limited to individual items, not crudités, cheese or fruit. For example, a glazed fig topped with mascarpone and wrapped with prosciutto is considered an "hors d'oeuvre," whereas figs on a platter are not.
-WIKIPEDIA