| Subject | English | Japanese |
| comp., MS | active mailbox | アクティブなメールボックス (A mailbox that has been accessed at least once in the last 30 days) |
| comp., MS | active mailbox migration | アクティブなメールボックスの移行 (The stage during the e-mail migration when the migration service is actively provisioning new cloud-based mailboxes) |
| comp., MS | Active Mailbox Subscriptions | アクティブ メールボックス サブスクリプション (A counter that measures how many active mailbox subscriptions there are at a given time) |