This odd looking word, *ghos-ti, is the Proto-Indo-European word which refers to the reciprocal relationships of hospitality. In fact, the English words "guest" and "host" both come from this root (the * at the beginning of the word just means that it's a word reconstructed by linguists and not attested in literature or archeology). Our religion in ADF is based on this idea, that we can form relationships with the Powers by making offerings to Them, with the expectation that we may receive blessings and wisdom from Them in return. Well, we've invented a new use for it!
At the Desert Magic Festival recently, during the closing ritual, this word suddenly became a spontaneous cheer or toast. Everyone ended the rite with a resounding, Ghosti!, which felt just right. Other cheers we've heard at the ends of rites, such as Hurrah! or Huzzah! or even (dare I say it?) Woof! just pale in comparison! So don't be surprised if you come across a group of ADFer's all happily cheering each other with this new toast: