The story
From kissing (noun) + ball (noun), from the custom of people kissing under the suspended ornament: see the 2001 quotation.
Etymology from Wiktionary, CC BY-SA 4.0.
kissing ball
kiss·ing ballToday it means: A hanging ornament, often used as a Christmas decoration, made by arranging plant parts, especially sprigs of holly or mistletoe, and evergreen leaves, into a ball shape. Full definition →