From The Collaborative International Dictionary of English v.0.48 :
Juglans \Jug"lans\, n. [L., walnut.] (Bot.)
A genus of valuable trees, including the true walnut of
Europe, and the America black walnut, and butternut.
[1913 Webster]
From WordNet (r) 3.0 (2006) :
Juglans
n 1: type genus of the Juglandaceae [syn: Juglans, genus
Juglans]