calomel Meaning, Definition & Usage

  1. noun a tasteless colorless powder used medicinally as a cathartic
    mercurous chloride.

WordNet

Cal"o*mel noun
Etymology
Gr. beautuful + black. So called from its being white, though made from a black mixture of mercury and corrosive sublimate. Cf. F. calomélas.
Definitions
  1. (Chem.) Mild chloride of mercury, HgCl, a heavy, white or yellowish white substance, insoluble and tastelles, much used in medichine as a mercurial and purgative; mercurous chloride. It occurs native as the mineral born quicksiver.

Webster 1913