Objects which have reached an age which makes them a witness of a previous era in human society.
In a consumer society an antique is above all an object whose atypical construction and age give it a market value superior to similar objects of recent manufacture.
Just about any object can become an antique if it survives long enough, but snob appeal or social acceptance only can ensure that it is actually worth something on the market place.
The term "antique" is used as an insult in some instances, usually to depreciate the usefulness of an object or a procedure. Those who reject the trappings of a consumer society reject the markets which inflate the monetary value of antique objects, regardless of their usefulness or esthetic qualities.
Any historical museum makes a considerable use of antiques in order to illustrate historical events and give them a practical context.