mistletoe

/ˈmɪsəlˌtoʊ/
noun
  1. A plant with small white berries that grows on trees, often used as a Christmas decoration. According to tradition, people standing under it must kiss.
    • We hung a sprig of mistletoe in the doorway for the holiday party.
    • The tradition of kissing under the mistletoe dates back centuries.
    • She blushed when he kissed her under the mistletoe at the office Christmas gathering.