cromniomancy

Noun

 * 1) Divination by onions or onion sprouts.
 * 2) * 1660, Robert Burton, The Anatomy of Melancholy in Brand Popular Antiquities (1844) iii.
 * Burton speaks of "cromnysmantia," a kind of divination with onions laid on the altar at Christmas Eve, practised by girls, to know when they shall be married, and how many husbands they shall have. This appears also to have been a German custom.