Choquet capacities, which are also referred to as fuzzy measures and cooperative games, model contributions and interactions over elements within a given set. They are used to encode the weights of the Choquet integral, a widely studied averaging aggregation function that can be applied to analysis and prediction tasks. This chapter introduces Choquet capacities in the context of aggregation functions, providing an overview of the related definitions and properties, as well as providing an example to help guide intuition on their behaviour and how they can be constructed.