Definition: An occurrent [span:Occurrent] at or in which processual entity [span:ProcessualEntity] entities can be located.

Comment: An instance of the spatiotemporal region [span:SpatiotemporalRegion] is a part of spacetime. All parts of spacetime are spatiotemporal region [span:SpatiotemporalRegion] entities and only spatiotemporal region [span:SpatiotemporalRegion] entities are parts of spacetime. In particular, neither spatial region [snap:SpatialRegion] entities nor temporal region [span:TemporalRegion] entities are in BFO parts of spacetime. Spacetime is the entire extent of the spatiotemporal universe, a designated individual, which is thus itself a spatiotemporal region [span:SpatiotemporalRegion]. Spacetime is among occurrents the analogous of space among continuant [snap:Continuant] entities.

Comment: All instances of occurrent [span:Occurrent] are spatiotemporal entities, that is, they enter in the relation of (spatiotemporal) location with spatiotemporal region [span:SpatiotemporalRegion] entities. As a particular case, the exact spatiotemporal location of a spatiotemporal region [span:SpatiotemporalRegion] is this region itself.

Comment: Spacetime and spatiotemporal region [span:SpatiotemporalRegion] entities are entities in their own rights which exist independently of any entities which can be located at them. This view of spacetime can be called "absolutist" or "the container view". In BFO, the class processual context [span:ProcessualContext] allows for a so-called relational view of spacetime, that is to say, a view according to which spatiotemporality is a matter of relative location between entities and not a matter of being tied to spacetime. In BFO, the bridge between these two views is secured through the fact that instances of processual context [span:ProcessualContext] are too spatiotemporal entities.

Examples: the spatiotemporal region occupied by a human life, the spatiotemporal region occupied by the development of a cancer tumor, the spatiotemporal context occupied by a process of cellular meiosis