A relationship between two events separated by distance in a temporal dimension, used by describing something as causal or acausal. A causal relationship is one such that the occurrence of one event is dependent upon the occurrence of the other. Thus describing a relationship as acausal means that the events in this relationship are not dependent upon each other. Describing a single event as acausal would imply that the event is not dependent upon any other event in order to manifest itself (I think this is impossible).

Examples:
Causal--: I cut my finger ---> My finger bleeds
Acausal--: I cut my finger ---> The phone rings