1) ADJ: usu ADJ n You use classical to describe something that is traditional in form, style, or content.

Fokine did not change the steps of classical ballet; instead he found new ways of using them.

...the scientific attitude of Smith and earlier classical economists.

2) ADJ: usu ADJ n Classical music is music that is considered to be serious and of lasting value.
3) ADJ: usu ADJ n Classical is used to describe things which relate to the ancient Greek or Roman civilizations.

...the healers of ancient Egypt and classical Greece...

It's a technological achievement that is unrivalled in the classical world.

...classical architecture.

4) ADJ: ADJ n A classical language is a form of a language that was used in ancient times and is now no longer used, or only used in formal writing.

...a line of classical Arabic poetry.

English dictionary. 2008.