Originally Posted by college_cook
I think hors d’oeuvre can be likened more to a canape', if you're talking about sit-down food. Easy to eat one-or-two bite dishes.
You are on the right track - a canapé can most certainly be an hors d'oevres - but it can also be an appetizer. A canapé is associated with a piece of bread, toast point, cracker, etc., such as pate, smoked salmon and caviar, etc., but they certainly fit the bill due to their one or two bites each.
A difference may be that an hors d'oeuvre may
be associated without benefit of an eating utensil, i.e., finger food. When you go to a cocktail party it may say "heavy hors d’oeuvres", which basically means there's no meal afterwards - they ARE the meal. They are usually one or two bites per "unit" and no more.
An appetizer is the first course TO a meal and normally served at the table.
The only time I think it would matter what the difference is is if you were at the White House/Royal Palace for a cocktail party - while "milling around" with the other guests I wouldn't say - GREAT appetizers!