From The Collaborative International Dictionary of English v.0.48 [gcide]:
Vitis \Vi"tis\, prop. n. [L., a vine.] (Bot.)
A genus of plants including all true grapevines.
[1913 Webster]
From WordNet (r) 3.0 (2006) [wn]:
Vitis
n 1: the type genus of the family Vitaceae; woody vines with
simple leaves and small flowers; includes a wide variety of
grapes [syn: Vitis, genus Vitis]