A classic is an outstanding example of a particular style, something of lasting worth or with a timeless quality. The word can be an adjective (a classic car) or a noun (a classic of English literature).

It denotes a particular quality in art, architecture, literature, design, technology, or other cultural artifacts. In commerce, products are named "classic" to denote a long standing popular version or model, to distinguish it from a newer variety.

Classic is used to describe many major, long-standing sporting events. Colloquially, an everyday occurrence (e.g. a joke or mishap) may be described as "an absolute classic". "Classic" should not be confused with classical, which refers specifically to certain cultural styles, especially in music and architecture: styles generally taking inspiration from the Classical tradition, hence classicism.

Source: Wikipedia