[1] : The Collaborative International Dictionary of English v.0.48

quassia \quas"sia\, n. nl. from the name of a negro, quassy,
   or quash, who prescribed this article as a specific.
   the wood of several tropical american trees of the order
   simarubeae, as quassia amara, picraena excelsa, and
   simaruba amara. it is intensely bitter, and is used in
   medicine and sometimes as a substitute for hops in making
   beer.
   1913 webster
see also:
simarubeae quassia amara picraena excelsa simaruba amara 

[2] : WordNet (r) 2.0

quassia amara
     n : 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
see also:
quassia bitterwood 

Quassia >> Q Words
Quassia, definition of term: Quassia
quassia_pag1.html

Amara >> A Words
Amara, definition of term: Amara
amara_pag1.html