First Online: 21 March 2016. 12 month embargo. / This paper presents cross-domain evidence that natural language makes use of (at least) two ways of individuating collective entities that differ in terms of how they cohere. The first kind, which I call swarm reference, picks out higher-order collective entities defined in terms of the spatial and temporal configuration of their constituent individuals. The second, which corresponds to canonical cases of group reference (e.g. committee, team, etc.), makes use of non-spatiotemporal notions. To motivate this distinction, I present systematic differences in how these two types of collective reference behave linguistically, both in the individual and event domains. These differences support two primary results. First, they are used as tests to isolate a new class of collective nouns that denote swarm individuals, both in English, as well as other languages like Romanian. I then consider a crosslinguistically common type of pluractionality, called event-internal in the previous literature (Cusic 1981, Wood 2007), and show that its properties are best explained if the relevant verbs denote swarm events. By reducing event-internal pluractionality to a type of collective reference also available for nouns, this work generates a new strong argument that pluractionality involves the same varieties of plural reference in the event domain that are seen in the individual domain.