According to gameranx.com, there are two Halo 4 Achievements related to the Terminals in Halo 4: Contact the Domain (find a Terminal in Campaign) and Terminus (find all Terminals). Gameranx has graciously supplied us with video walkthroughs for all the Terminals available thus far.
Terminal 1 – Requiem
Terminal 2 – Forerunner
Terminal 3 – Infinity
Terminal 4 – Reclaimer
Terminal 5 – Shutdown
Terminal 6 – Composer
Terminal 7 – Midnight