Lewis & Short

jūglans, glandis, f. [i. q. Jovis glans = Gr. Διὸς βάλανος], a walnut; a walnut-tree: haec glans optima, et maxima, ab Jove et glande juglans appellata est, Varr. L. L. 5, § 102 Müll.: juglandium putamina, Cic. Tusc. 5, 20, 58: juglandium umbra, Plin. 17, 12, 18, § 89.
Also with nux: nuces juglandes, Plin. 15, 22, 24, § 86.