What is an art, according to Socrates?

An art is a definable body of knowledge or an order system of skills. It is important to mention that all arts have a (perhaps divinely inspired) creative facet. Poetry, for example, is a skill that can be mastered, taught, and analyzed, but the creative forces which move a poet to write - or in this case that move Ion to memorize Homer - are not quantifiable quite like the aforementioned skill of poetry. Therefore, an art is not just a skill, but also a term used to appeal to the otherworldly inspiration that one gets from art's product.