Mambo is the term for a female (as opposed to the Houngan, or male) High Priest in the Vodou religion in Haiti.
Mambo are the highest form of female clergy in the religion, whose responsibility it is to preserve the rituals and songs and maintain the relationship between the spirits and the community as a whole (though some of this is the responsibility of the whole community as well). They are entrusted with leading the service of all of the spirits of their lineage.
There are two ranks of mambo, mambo asogwe (high priestess) and mambo si pwen / mambo sur point ("junior priestess"). A mambo asogwe is the highest female member of clergy in vodou; she is the only one with authority to ordain other priests (a responsibility shared by Houngan Asogwe, the title for a male High Priest. Vodou does not impose particular responsibilities or limitations based on gender; titles may differ, but the tradition has open gender parity.)