Definition:
A Role is the name given to an Entity when it's
participating in an Event.
Examples include Barrier,
Container, and Product, in
which the Entity "playing the role" is participating in the Events
of Block, Be-Contained, and
Produce, respectively.
More information on Roles, including the ways in which Roles differ
from Entities and the way to represent Roles in SHAKEN, will be
forthcoming.