A plant with rounded leaves and white berries. It's often associated with Christmas, where there is a tradition of kissing under branches of mistletoe.
Not to be confused with holly, which is another plant with spiky leaves and red berries. While red-berried species of mistletoe do exist (Viscum cruciatum, Viscum rotundifolium) they still lack spiky leaves.
The following tags implicate this tag: holding_mistletoe (learn more).