coven (noun) - a formal assembly of witches; a meeting of any group with similar interests or activities [kuhv-uhn]
BREAKDOWN: CO- (together) + VEN- (to come)
a convent is a community of nuns or others devoted to religious life under a superior, or the building housing such a community
to convene means to come together or assemble for an official purpose
“Your average witch is not, by nature, a social animal as far as other witches are concerned. There's a conflict of dominant personalities. There's a group of ringleaders without a ring. There's the basic unwritten rule of witchcraft, which is 'Don't do what you will, do what I say.' The natural size of a coven is one. Witches only get together when they can't avoid it.” —Terry Pratchett