dihedral /daɪˈhiːdɹəl/adjective 3noun 3forms 1 adjective3 •Consisting of, relating to or contained between two plane surfaces. •Having wings that form a dihedral angle, especially when the angle between the upper sides is less than 180°. •Of wing pairs, inclined at an upward angle to each other. noun3 •An angle between two plane surfaces •The upward slope of an aircraft's wing •The angle between pairs of chemical bonds separated by a third bond formsdihedrals