The Collaborative International Dictionary of English v.0.48:

Cha \Cha\ (ch[aum]), n. [Chin. ch`a.] [Also chaa, chais,
   tsia, etc.]
   Tea; -- the Chinese (Mandarin) name, used generally in early
   works of travel, and now for a kind of rolled tea used in
   Central Asia.

         A pot with hot water . . . made with the powder of a
         certain herb called chaa, which is much esteemed. --Tr.
                                                  J. Van
                                                  Linschoten's
                                                  Voyages
                                                  (1598).
   [Webster 1913 Suppl.]