Limes deals with two separate types of entities: Resources are strictly those things whose usage value refers to a consumption at a specific point in time, and where quota is the upper limit on usage at each individual point in time. In contrast, rates are all those things where the usage is accumulated over time, and there can be a limit of how much usage can occur within a certain window of time.
The Limes API has therefore been split into two separately documented sub-specifications: