- any of several astringent substances obtained from various tropical plants, especially from the wood of two East Indian acacias, Acacia catechu and A. suma: used in medicine, dyeing, tanning, etc.
- a water-soluble astringent resinous substance obtained from any of certain tropical plants, esp the leguminous tree Acacia catechu of S Asia, and used in medicine, tanning, and dyeing
