sodium carbonateBrE /ˌsəʊdiəm ˈkɑːbənət/ 🔊NAmE /ˌsoʊdiəm ˈkɑːrbənət/ 🔊 (also ˈwashing soda) noun [uncountable] (symbol Na2CO3) a chemical in the form of white crystals or powder that dissolves and is used in making glass, soap and paper, and for making water soft 碳酸钠