Quassia \Quas"si*a\, 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 Simarube[ae], as Quassia amara, Picr[ae]na excelsa, and Simaruba amara. It is intensely bitter, and is used in medicine and sometimes as a substitute for hops in making beer.

Source: Webster's Revised Unabridged Dictionary (1913)