WordNet (r) 3.0 (2006):

lignum vitae
    n 1: hard greenish-brown wood of the lignum vitae tree and other
         trees of the genus Guaiacum [syn: lignum vitae, guaiac,
         guaiacum]
    2: small evergreen tree of Caribbean and southern Central
       America to northern South America; a source of lignum vitae
       wood, hardest of commercial timbers, and a medicinal resin
       [syn: lignum vitae, Guaiacum officinale]