Matriarchy
From Memory Alpha, the free Star Trek reference.
A matriarchy is a society in which females hold a dominant role over males. The opposing sociological structure is a patriarchy.
There have been numerous examples of matriarchal societies throughout history, including the inhabitants of Cygnet XIV and Angel I, and the Skrreea of the Gamma Quadrant. (TOS: "Tomorrow is Yesterday"; TNG: "Angel One"; DS9: "Sanctuary") The Paraagans were once ruled by a matriarchy, though it has become more egalitarian since the 2140s. (ENT: "Shockwave")
According to Deanna Troi, Betazoid society also has matriarchal elements. (TNG: "Angel One")
In 2373, Tova Veer speculated that Humans might have a matriarchal society, after observing the hierarchy of the USS Voyager crew under Captain Kathryn Janeway. (VOY: "Distant Origin")
