Definition of ETHNOMEDICINE. : the comparative study of how different cultures view disease and how they treat or prevent it; also: the medical beliefs and practices of indigenous cultures.
Ten materials familiar to various prehistoric cultures are now known to be chemical elements: Carbon, copper, gold, iron, lead, mercury, silver, sulfur, tin, and zinc. Three additional materials now accepted as elements, arsenic, antimony, and bismuth, were recognized as distinct substances prior to 1500 AD.
A chemical element or element is a chemical substance consisting of atoms having the same number of protons in their atomic nuclei (i.e. the same atomic number, Z).s a special case, the three naturally occurring isotopes of the element hydrogen are often specified as H for 1 H (protium), D for 2 H (deuterium), and T for 3 H (tritium). This convention is easier to use in chemical equations, replacing the need to write out the mass number for each atom.