The word classic has several meanings. In general, these meanings refer to some past time. "classic" should not be confused with classical, something that is classical is not necessarily a classic, but the word classic has more meanings. Such as:
A work of popular culture that inspires devotion or respect is often called a classic.
Something exhibiting a timeless quality or feel.
An artistic work of lasting worth.
Of the first or highest quality, class, or rank.
Of or adhering to an established set of artistic or scientific standards or methods.
Basic; fundamental.
Of literary or historical renown.
Definitive.
An artist or artistic production considered a standard.