A ship in The Fleet. During the events of Laura Roslin's incarceration, all 12 delegates from the Quorum of Twelve were enroute from this ship to the Galactica. (Fragged)
Lt. Felix Gaeta discovered fraudulent ballots for Laura Roslin in Zephyr's ballot box during the election in Lay Down Your Burdens, Part II.
Note
The ship is likely named after the Greek god of the western wind, Zephyrus.