lignum vitae

noun

1. either of two tropical American trees, Guaiacum officinale or G. sanctum, of the caltrop family, having very hard, heavy wood.
2. the wood of such a tree, used for making pulley blocks, mallet heads, bearings, etc.
3. any of several other trees yielding a similar hard wood.

noun

1. either of two zygophyllaceous tropical American trees, Guaiacum officinale or G. sanctum, having blue or purple flowers
2. the heavy resinous wood of either of these trees, which is used in machine bearings, casters, etc: formerly thought to have medicinal properties