An SNMPv3 user is a network management user that is authorized to access and manipulate information on a network using the Simple Network Management Protocol version 3 (SNMPv3). SNMPv3 is a protocol used to manage and monitor network devices, such as routers, switches, and servers. It provides authentication and encryption features to ensure secure access to network devices. SNMPv3 users are defined by their security credentials and access rights, including a username, authentication key, encryption key, and access privileges. With these credentials, SNMPv3 users can retrieve and modify network information, configure network devices, and perform other management tasks.