Legal definitions will be examined from three perspectives: their pragmatic function, their propositional structure, and their argumentative role. In law, definitions can be used for different pragmatic purposes: they can be uttered to describe a concept, or to establish a new meaning for a term. The propositional content of definitional speech acts can be different. In law, like in ordinary conversation, there might be different types of definition: we can define by providing examples, or showing the fundamental characteristics of the (...) concept defined, or listing the constituent parts of the denotatum. All these definitions play different argumentative roles in legal discourse. At a third level, definitions can be thought of as premises in complex patterns of reasoning (for the subject of reasoning from definition in law, see Aarnio 1977; Moore 1980; Lindahl, 2004). They constitute the fundamental element of argument from classification, namely a pattern of inference in which a new property (or a name) is attributed to an entity on the basis of other properties. (shrink)