What is the term for grouping AWS accounts together for simplified management?

The term for grouping AWS accounts together for simplified management is "Organizational unit (OU)." In the context of AWS Organizations, an organizational unit is a container that can hold AWS accounts and other OUs. This structure allows organizations to manage billing, apply policies, and simplify the administration of multiple AWS accounts from a hierarchical standpoint.

OUs are beneficial for policy management as they enable administrators to apply Service Control Policies (SCPs) to either an entire OU or specific accounts within it. This way, management teams can standardize controls and security across various teams or departments in the organization while maintaining the flexibility of account-specific configurations.

The other terms do not accurately reflect the AWS feature set. For example, "Account Group" and "Account Set" aren't recognized terminologies in the AWS ecosystem for managing accounts. "Business Unit (BU)" usually refers to divisions within a company rather than a feature for grouping accounts in AWS, which makes it less applicable in this specific context.