Final answer:
In computing, a User can function as both a subject, who initiates actions, and an object, the entity being referenced or acted upon, depending on the context.
Step-by-step explanation:
Within the context of computing, the entity that can operate as both a subject and an object is a User. A user is an entity that interacts with a computer system, and this entity is typically assigned a unique identifier (such as a username) to manage access and operations. In various security and access control models, the term 'subject' typically refers to an active entity that requests access to a resource or data (like a file or program), while 'object' refers to the passive entity that contains the resource or data.
For example, a user (subject) may request to open a file (object) on their computer. Conversely, in systems that log user activities, the same user might be referenced as an object in the logs (e.g., 'User XYZ accessed file ABC'). This flexibility allows the user to be both the initiator of an action and the target of system operations or policies, depending on the context in which the user-entity is being referenced.