adj. 1.of a light brown or yellowish brown color hazel n. 1.Australian tree grown especially for ornament and its fine-grained wood and bearing edible nuts 2.the fine-grained wood of a hazelnut tree (genus Corylus) and the hazel tree (Australian genus Pomaderris) 3.any of several shrubs or small trees of the genus Corylus bearing edible nuts enclosed in a leafy husk