Thanks guy :)
The group is made up of more than just me.
The Sabbath is a holy day. A sabbat is a witches meeting. Same origin, but it is a little disconcerting to see Sabbath used for sabbat.
Wikipedia says they're interchangeable. http://en.wikipedia.org/wiki/Witches%27_SabbathShow me evidence if that's not correct.
A Witches' Sabbath is the same as a sabbat. From http://en.wikipedia.org/wiki/Sabbath#Wicca we get 'Eight sabbats (occasionally "sabbaths", or "Sun sabbats")...', so occasionally sabbath is used, but it is not the norm. I personally have never seen sabbath used that way before.