Master is an archaic naval term (not a rank) for the commanding officer of a vessel. It has the advantage of denoting that status in officers who do not (necessarily) hold the rank of captain. In the 23rd century, a master's license was required in order to operate a space vessel. (TOS: "Mudd's Women")
- Harcourt Fenton Mudd claimed to have a master's ticket allowing him to command the merchant Class J cargo ship. The license was revoked on stardate 1116.4, forcing Mudd to impersonate Captain Leo Walsh, who presumably was a master in good standing before his untimely demise. (TOS: "Mudd's Women")
- "Master" was the title given to Kojiro Vance, the commanding officer of the Kobayashi Maru. (Star Trek II: The Wrath of Khan)
- In the opening sequence of Star Trek VI: The Undiscovered Country, Captain Sulu dictates his log entry, where he refers to himself as "master of this vessel".
Master is also a title adopted formally or informally by some religious or political leaders, or an honorific title denoting great prowess in a particular field (such as chess or martial arts).
- It was also the title used by Dukat as leader of the Cult of the Pah-wraiths. While he didn't refer to himself directly as master, his Bajoran "children" did. (citation needed • edit)
- In the cult's community aboard Empok Nor, it was required that one get permission from "the master" before conceiving a child. (DS9: "Covenant")