macadamia Syllabification: (mac·a·da·mi·a)Pronunciation: /ˌmakəˈdāmēə/Definition of macadamia noun 1 (also macadamia nut) the edible nut of the macadamia tree. 2the Australian tree that produces the macadamia nut, with slender, glossy evergreen leaves. Genus Macadamia, family Proteaceae: several species, especially M. integrifolia and M. tetraphylla, which are cultivated for their nuts Origin:modern Latin, named after John Macadam (1827–65), Australian chemistmacadamia in other Oxford dictionaries Definition of macadamia in the British & World English dictionary