The Collaborative International Dictionary of English v.0.48:

Bitterwood \Bit"ter*wood`\, n.
   A West Indian tree (Picr[ae]na excelsa) from the wood of
   which the bitter drug Jamaica quassia is obtained.
   [1913 Webster]

WordNet (r) 3.0 (2006):

bitterwood
    n 1: handsome South American shrub or small tree having bright
         scarlet flowers and yielding a valuable fine-grained
         yellowish wood; yields the bitter drug quassia from its
         wood and bark [syn: quassia, bitterwood, Quassia
         amara]
    2: West Indian tree yielding the drug Jamaica quassia [syn:
       Jamaica quassia, bitterwood, Picrasma excelsa,
       Picrasma excelsum]
    3: medium to large tree of tropical North and South America
       having odd-pinnate leaves and long panicles of small pale
       yellow flowers followed by scarlet fruits [syn: paradise
       tree, bitterwood, Simarouba glauca]