anhedral Syllabification: (an·he·dral)Pronunciation: /anˈhēdrəl/Definition of anhedral adjective Crystallography (of a crystal) having no plane faces. noun Aeronautics downward inclination of an aircraft’s wing, or the angle of this. Compare with dihedral.Origin: late 19th century (as an adjective): from an-1 'not' + -hedral (see -hedron)anhedral in other Oxford dictionaries Definition of anhedral in the British & World English dictionary