The chemical element (symbol Ba) with an atomic number of 56. It is a soft, reactive, silvery alkaline earth metal. / (countable) A single atom of this element. / (medicine) barium sulfate suspension.

plural of barium

(inorganic chemistry) The barium salt of arsenic acid, Ba₃(AsO₄)₂, formed as a precipitate when removing arsenic from water supplies.

(inorganic chemistry) The barium salt of hydrochloric acid, BaCl₂; it is toxic, and has been used as a rat poison.

(inorganic chemistry) The barium salt of thiocyanic acid, Ba(SCN)₂, used in photography and in dyeing

(medicine) A preparation of barium sulfate (a radioopaque compound) which the patient ingests for the purpose of producing clear radiographs of the esophagus, stomach, and duodenum.

plural of barium meal

(astronomy) Any of a class of giant stars whose spectra show the presence of s-process elements (such as barium)

plural of barium star

alternative form of barite.