An Interaction Affordance that describes a source, which asynchronously pushes data to Consumers.

Affordance that exposes state of the Thing, which be retrieved and/or updated.

Metadata of a Thing that shows how Consumers may interact with the Thing. Although many types of affordances are possible, W3C WoT only defines three.

Affordance that invokes a method of the Thing to manipulates state or triggers a process on the Thing.