Cratylism as a philosophical theory reflects the teachings of the Athenian Cratylus. The term in philosophy comes about from Plato's Socratic dialogue, Cratylus. Within the dialogue, those philosophical positions of Hermogenes and Cratylus are now what are referred to as 'conventionalism' and 'naturalism.' According to Cratylism, there is a natural relation between word and thing.
Plato's Socratic dialogue, Cratylus, Cratylus discusses the 'correctness of names.' If the name of an object, word, or phrase is the correct name for that particular thing, what is it exactly that makes this true? The conventionalist Hermogenes contends that convention and agreement alone are what determine the correctness of names. Cratylus believes that names cannot just be given out at the will of convention or convenience; he holds that names have a natural belonging to their objects.
There is also heavy and credited speculation of Socrates' humor in the dialogue. Socrates can be read as dismissing naturalism; and thus everything he says should be regarded as simply making fun of the etymological practice of 'names.'