mac·a·da·mi·a nut (māk'ə-dā'mē-ə) n. The round, hard-shelled nut or the edible seed of the Australian tree Macadamia ternifolia, now cultivated in Hawaii.
[New Latin Macadamia, genus name, after John Macadam (1827-1865), Scottish-born Australian chemist.]
"Australian evergreen tree," 1904, from Mod.L. (1858), named for Scot.-born chemist Dr. John Macadam (1827-65), secretary of the Victoria Philosophical Institute, Australia.