borax

A white or gray/grey crystalline salt, with a slight alkaline taste, used as a flux, in soldering metals, making enamels, fixing colors/colours on porcelain, and as a soap, etc.

The sodium salt of boric acid, Na2B4O7, either anhydrous or with 5 or 10 molecules of water of crystallisation; sodium tetraborate.

(sometimes attributive) Cheap or tawdry furniture or other works of industrial design.