Source : Webster's Revised Unabridged Dictionary (1913)

Catechu \Cat"e*chu\, n. [See {Cashoo}.] (Chem.)
   A dry, brown, astringent extract, obtained by decoction and
   evaporation from the {Acacia catechu}, and several other
   plants growing in India. It contains a large portion of
   tannin or tannic acid, and is used in medicine and in the
   arts. It is also known by the names {terra japonica},
   {cutch}, {gambier}, etc. --Ure. --Dunglison.

Source : WordNet®

catechu
     n 1: extract of the heartwood of Acacia catechu used for dying
          and tanning and preserving fishnets and sails; formerly
          used medicinally [syn: {black catechu}]
     2: East Indian spiny tree having twice-pinnate leaves and
        yellow flowers followed by flat pods; source of black
        catechu [syn: {Jerusalem thorn}, {Acacia catechu}]