A system of symbols and notation for the chemical elements and the combinations of these elements which form numerous chemical compounds. This system of symbols, devised since about 1800 by chemists, consists of letters, numerals, and marks that are designed to denote the chemical element, formula, or structure of the molecule or compound. These symbols give a concise and instantly recognizable description of the element or compound. In many cases, through the efforts of international conferences, the symbols are recognized throughout the scientific world, and they greatly simplify the universal languge of chemistry.