Actual is a term for the principal officer in command.
A real-world communications term signifying that the officer-in-charge (e.g. the commander of a military vessel, task force or unit) is speaking or required on-air.
Used to distinguish the commanding officer from other personnel who may use the communications channel, without recourse to code names or other means of identification. Frequently used when sensitive information needs to be communicated directly to the officer-in-charge.
William Adama is known as Galactica's Actual.