lig·num vi·tae 
(lĭg′nəm vītē)
(lĭg′nəm vītē)n. pl. lignum vitaes
1. Any of several tropical American trees of the genus Guaiacum, especially G. officinale or G. sanctum, having evergreen leaves and very heavy, durable, resinous wood.
2. The wood of any of these trees, the hardest of commercial woods.
[New Latin lignum vītae : Latin lignum, wood + Latin vītae, genitive of vīta, life.]