Hello,
It seems it is a religious ceremony, more commonly these days used specifically to refer to communion. I've added these two senses. I can't see anything that is directly linked to the Mormon church, but if neither of these senses sounds like what you are looking for, please let me know and I will do some further research.
The new senses I have added will be included in future translation projects to other languages and they will appear in the dictionaries once they've been translated.