A member account is an AWS account, other than the management account, that is part of an organization in AWS Organizations. If you are an administrator of the management account in an organization, you can create member accounts in the organization and invite existing accounts to join the organization. A member account can belong to only one organization at a time.
Member accounts can use AWS Artifact Account Agreements to accept or terminate agreements on behalf of that individual member account only. Member accounts can use AWS Artifact Organization Agreements to view the agreements accepted on the member account’s behalf by the organization’s management account.