The Collaborative International Dictionary of English v.0.48:

Mate \Ma"te\ (m[aum]"t[asl]), n. [Sp.]
   The Paraguay tea, being the dried leaf of the Brazilian holly
   (Ilex Paraguensis). The infusion has a pleasant odor, with
   an agreeable bitter taste, and is much used for tea in South
   America.
   [1913 Webster]