Tau Ceti is the name of the second-closest star to the Sun (after Alpha Centari A).

In-universe, Tau Ceti IV is named as the planet the Varia was on course for, mentioned in Where are you?

Though unconfirmed, this name may be a reference to Tau Ceti IV as mentioned in Star Trek II: The Wrath of Khan (1982), a named star invented for the Kobayashi Maru test for character in command-track cadets of Starfleet Academy.