Thanks to interior designer/stylist Scot Meacham Wood, I 've learned a new word. Bobeche is the little cup at the base of the candle. It's usefulness is a hold-over from an earlier time when the bobeche would catch dripping wax from the burning candles. In modern pieces, especially in the crystal fixtures, they are also used to hang decorative prisms. As a more decorative element, it is also used at the top of the fixture - just below the mounting "hanger loop."