 The traditional account of definitions should not be viewed as requiring definitions to be in normal form. The only requirements that it imposes are (i) that the definiendum contain the defined term; (ii) that the definiendum and the definiens belong to the same logical category; and (iii) the definition satisfies Conservativeness and Eliminability. So long as these requirements are met, there are no further restrictions. The definiendum, like the definiens, can be complex; and the definiens, like the definiendum, can contain the defined term. So, for example, there is nothing formally wrong if the definition of the functional expression ‘the number of’ has as its definiendum the formula ‘the number of \(F\)s is the number of \(G\)s’. The role of normal forms is only to provide an easy way of ensuring that definitions satisfy Conservativeness and Eliminability; they do not provide the only legitimate format for stipulatively introducing a term. Thus, the reason why (4) is, but (6) is not, a legitimate definition is not that (4) is in normal form and (6) is not.