an implementation independent unit of responsibility that performs an action to achieve an effect that contributes to a desired end state.
NATO Architecture Framework (NAF) Chapter 3, NNEC Architecture Elements and Descriptions
For the concept of the architecture element ‘actor’ different names are used. Common similar terms are: Business Actor, Performer, Logical Node.
An actor in the context of Air Navigation Service Providers (ANSP) can be an organisation/unit like an ATS unit (ACC,APP, TWR) or an individual like an air traffic controller, planning controller, executive controller, etc.
Lexicon Release 2015.2