 The nature and existence of properties have always been central and controversial issues in philosophy since its origin, and interest in them keeps flourishing, as Allen’s (2016) recent introductory text well testifies (see also surveys or anthologies such as Loux 1972; Oliver 1996; Mellor and Oliver 1997; Koons and Pickavance 2017; Marmodoro and Mayr 2019). At least since Plato, who called them “ideas” or “forms”, properties are viewed as universals, i.e., as capable, (in typical cases) of being instantiated by different objects, “shared” by them, as it were; consequently, in contrast with particulars, or individuals, of being somehow at once in different  places.[1]  For example, if there are two potatoes each of which weighs 300 grams, the property weighing 300 grams is instantiated by two particulars and is therefore multi-located. According to a different conception, however, properties are themselves particulars, though abstract ones. As so conceived, properties are nowadays commonly called  tropes,  and are the subject of another entry. Here we shall focus on properties as universals. Relations, e.g., loving and between, can also be considered properties: they are predicable, exemplifiable, and viewable as universals. Accordingly, we use “property” as a generic term that also covers them, unless the context suggests otherwise. However, we shall consider their peculiarity only to a minimum extent, since they are discussed in detail in the entry on  relations.