barium (n.)
1808, coined in Modern Latin by its discoverer, English chemist Sir Humphrey Davy (1778-1829), because it was present in the mineral barytes "heavy spar" (barium sulphate), so named by Lavoisier from Greek barys "heavy," from PIE root *gwere- (1) "heavy." The metal is actually relatively light. With chemical ending -ium. Related: Baric.