Meaning of borax pentahydrate

bo'rax pentahy'drate

Pronunciation: [key]
— Chem. Chem.
  1. a white, crystalline, water-soluble solid, NaBO&multiplydot;5HO, used chiefly for killing weeds, as a water softener, and as a disinfectant and deodorizing agent.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.