Mambo is the term for a female (as opposed to the Houngan, or male) High Priest in the Vodou religion in Haiti. They are the highest form of 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 priest) and mambo sur pwen / mambo sur point ("junior priest"). A mambo asogwe is the highest member of clergy in vodou; she is the only one with authority to ordain other priests.