International audience What semantics should we attribute to mass expressions like "wisdom" and "love", which are derived from gradable expressions ("wise", "to love")? We first examine how these expressions are used, then how they are interpreted in their various uses. We show in particular that, just like with ordinary concrete mass nouns ("wine", "furniture"), sentences where they appear are liable to distributive, collective, and intermediate construals. We then propose a model to account for these data, in which derived mass expressions denote instances of properties. The model is general enough to apply both to concrete and derived mass nouns. This establishes that mass nouns have a uniform semantics. Another feature of the account is that, to explain the gradability of mass expressions, it makes use of degrees and measure functions only when these are overtly expressed, in expressions like "a lot of wisdom" and "two litres of wine".