–adjective
1.
of or belonging to the past; not modern.
2.
dating from a period long ago: antique furniture.
3.
noting or pertaining to automobiles approximately 25 years old or more.
and then...
noun
8.
any work of art, piece of furniture, decorative object, or the like, created or produced in a former period, or, according to U.S. customs laws, 100 years before date of purchase.
9.
the antique style, usually Greek or Roman, especially in art.
So.. the definitions are confusing too. But according to US customs, 100 years old. So I guess we should go by what the US says. :)