WordNet (r) 3.0 (2006):

beech family
    n 1: chiefly monoecious trees and shrubs: beeches; chestnuts;
         oaks; genera Castanea, Castanopsis, Chrysolepis, Fagus,
         Lithocarpus, Nothofagus, Quercus [syn: Fagaceae, family
         Fagaceae, beech family]