D / dĭăgōnālis
adjective

dĭăgōnālis

neut. dĭăgōnāle
[from διαγώνιος and the Lat. ending alis)
diagonal
diagonal: linea, Vitr. 9, 1; 6, 5.—And subst., dĭăgōnĭum, ii, n.: diagonii linea, id. 6, 4.