walnut one of the finest nuts of temperate regions. There are a dozen species of walnut tree with edible nuts, in a family which also includes the pecan and other trees which bear hickory nuts. The most important species is the Persian walnut, Juglans regia; sometimes called ‘English walnut’ in the USA. This large and beautiful tree is found wild over a broad area from SE Europe through temperate Asia, most of the way to China.
The fruit is a green drupe, with flesh surrounding a hard-shelled stone or nut. Inside the nut is the edible kernel.