  Here Aristotle seems to be suggesting that some relative terms fail to signify genuine relations. Although terms such as ‘head’ and ‘hand’ clearly count as relative—since predications of the form ‘x is a head’ and ‘x is a hand’ are more perspicuously represented as of the form ‘x is a head of y’ and ‘x is a hand of y’—these terms signify parts of substances rather than relations. On the basis of these and other such examples, the medievals conclude that relations must be identified not with the items signified by relative terms, but rather with a proper subset of them.