The title of the ruler of the Ferengi Alliance, master of its commerce and keeper of the Rules of Acquisition, held by Zek and passed to Rom in 2375.
The Grand Nagus is the political and financial head of the Ferengi Alliance. He rules from the Tower of Commerce on Ferenginar, grants trade franchises and takes a share of much of the profit earned by his people. His badge of office is a staff topped with a gold-pressed latinum likeness of a Ferengi head, which subjects kiss in greeting. The first holder was Gint, author of the Rules of Acquisition.
Grand Nagus Zek is introduced in the Deep Space Nine episode The Nagus, in which he fakes his death and names Quark as successor in order to test his own son Krax. He returns in episodes including Rules of Acquisition, Prophet Motive and Ferengi Love Songs.
In The Dogs of War Zek retires to Risa with Ishka and names Rom as the next Grand Nagus, to Quark's horror. Rom still holds the office in Lower Decks.