A Sister Coven is a coven that is close to another Coven, the leaders are close friends and the Covens can be a sanctuary to each other, as well as sharing resources, materials etc.
Most people who practace peganisam are wemen i not a women but alot of covens keep to that becuse in the old pegan groupes they were the shawmens its odd but even thow that was thousands of years agao it still genaraley stays that way kinda outdated