a large tall tree with spreading branches, white or pink flowers and nuts that grow inside cases that are covered with short spikes 七叶树；马栗 
the smooth brown nut of the horse chestnut tree 七叶树的坚果
Word Originlate 16th cent.: translating (now obsolete) botanical Latin Castanea equina; its fruit is said to have been an Eastern remedy for chest diseases in horses.