What is Classics?
In the World at Large
The word "classic" is used in the world at large in several overlapping senses, each of them legitimate in their own context, but sometimes confusing in the aggregate. It may be used, for instance, to refer to a work of high authority or of great historical importance in a particular field. So Darwin's Origin of Species could be described as a classic work of biology.
The word is also used to describe certain formal or aesthetic properties, such as the style of a dress or the line of a gold swing. Here it typically suggests gracefulness, simplicity, or restraint, a lack of clutter. As a term of style it is sometimes contrasted to "baroque" or (especially) to "romantic".
In the realm of literature, writers tend to use "classic " in a doubly evaluative sense, to refer to a literary work of high merit, but also of well established reputation. In this sense, Shakespeare and Jane Austen, and a large number of other writers ancient and modern, have a perfectly fair claim to be called classics. In fact, American students entering college often have this idea in mind when they think of classics--a sequence of great books, extending from antiquity to modern times, excluding only books so recently written as not to have been tested critically beyond the writer's own generation.
In the University
In a university setting, however, "classics" means something at once more specific and less restrictive than "great books". On the one hand, more specifically, it refers to the writings of Greek and Roman antiquity. It serves to denote a period, leaving open the question whether individual works deserve to be called "classic" in any evaluative sense. On the other hand, in the less restrictive sense, it encompasses not only literature but the whole social, material, and intellectual culture of the ancient Greek and Roman worlds, from the Bronze Age to (say) the publication of the code of Roman law in Byzantium some 2,000 years later.
Classics in this broad sense includes the study of language and creative literature, of political and social history, of economics and law, of philosophy, religion, and art, and of the material remains of the ancient world. The organizing idea of the field is not a method or a discipline, but the culture of Greco-Roman antiquity in all it richness and diversity (often its strangeness). Classics in this sense is the original and most wide ranging of interdisciplinary fields.
What then, in practical terms, does a student of Classics actually do? A traditional and still valuable curriculum emphasizes the study of language and, at the advanced level, the reading of literary texts in their original Latin or Greek, with the aid of commentaries. On this basis, a student can then, usually in graduate school, pursue more specialized study. An alternate approach is to study antiquity through works in English translation. This method offers the student a quicker access to a wider range of materials, though it limits the depth in which study can be pursued. For the student whose real passions lie elsewhere, but who is curious about the ancient world, this may be the best way to proceed.
A Last Word
A last word about the meaning of "classic(s)". Students of Classics in the broad sense outlined above do not for the most part presume, if they ever did, that everything thought or made in antiquity qualifies as "classic" in the evaluative sense. The curriculum, especially the undergraduate curriculum, naturally emphasizes the greater over the lesser figures--you are more likely to read Homer and Virgil than Nicander and Persius. But any ancient work that bears the reputation of being "classic" in the sense of possessing high merit has always to be earning that reputation again from a new generation of readers. Antiquity, properly appreciated, does not get to rest on its laurels.