Definition of "blackbutt"
(chiefly Australia) Any of several Australian eucalyptus trees with a dark fibrous bark towards the base of the trunk, especially Eucalyptus pilularis, but also Eucalyptus zopherophloia and Eucalyptus todtiana.
Quotations
Bothered by the conviction of making no impression on her, he pulled up at a strip of road shaded by tall spotted gums, blackbutt, and honeysuckle, and produced a packet of cigarettes. "About time for a smoke-O," he said, "Have a fag, Cora.'
1938, Norman Lindsay, Age of Consent, 1st Australian edition, Sydney, N.S.W.: Ure Smith, published 1962, page 169