Definition of blackboy
- an Australian tree or erect shrub with long, stiff grass-like leaves. Flowering in some species is stimulated by fire. Also called grass tree.
- Genus Xanthorrhoea, family Xanthorrhoeaceae: several species, including a tree (X. preissii) with a thick dark trunk and a palm-like crown of leaves, and a shrub (X. australis) with a short buried trunk and leaves on the surface of the ground