The Collaborative International Dictionary of English v.0.48:

Piassava \Pi*as"sa*va\, n. [Pg. piasaba.]
   A fibrous product of two Brazilian palm trees (Attalea
   funifera and Leopoldinia Piassaba), -- used in making
   brooms, and for other purposes. Called also pia[,c]aba and
   piasaba.
   [1913 Webster]