a colorless, toxic, crystalline powder, NaF, with many uses, esp. as an insecticide, in making glass, and, in minute quantities, in toothpaste and to fluoridate public water supplies
See sodium fluoride in American Heritage Dictionary 4
noun
A colorless crystalline salt, NaF, used in fluoridation of water, in treatment of tooth decay, and as an insecticide and a disinfectant.