Expressivists of all sorts think that moral sentences are conventional devices for expressing pro and con attitudes towards their objects. In this broad sense emotivists are expressivists; they agree that moral language functions to express non-cognitive attitudes of various sorts.  The claim that moral terms function much like ‘boo’ and ‘hurrah’ qualifies as expressivist in a broad sense.  In recent years, however, the term ‘expressivist’ has come to be used in a narrower way, to refer to views which attempt to construct a systematic semantics for moral sentences by pairing them with the states of mind that the sentences are said to express.  Such expressivists hold that the meanings of all sentences containing moral terms are determined by the mental states that they serve to express.