iconic symbol
a linguistic sign (written or spoken word) that has a physical resemblance, rather than an arbitrary relation, to its referent. Examples include onomatopoeic coinages, such as choo-choo (train), and the signs used in pictographic languages. With these few exceptions, linguistic signs are held to be arbitrary in most modern thinking on language. The contrary view, which holds that there is a general if hidden correspondence between the sounds of words and their referents, is known as the theory of phonetic symbolism. Compare arbitrary symbol.