Properties and concepts are similar kinds of thing in so far as they are both typically understood to be whatever it is that predicates stand for. However, they are generally supposed to have different identity criteria: for example, heat is the same property as molecular kinetic energy, whereas the concept of heat is different from the concept of molecular kinetic energy. This paper examines whether this discrepancy is really defensible, and concludes that matters are more complex than is generally thought. The distinction between canonical and non-canonical designators, as applied to such entities as propositions, properties and concepts, is examined, as are causal realist accounts of the semantics of such terms as ‘electricity’ and ‘mass’.