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.
Every chemical element has one or more isotopes. 1  An atom is first identified and labeled according to the number of protons in its nucleus. This atomic number is ordinarily given the symbol Z. 2  Not all the atoms of an element need have the same number of neutrons in their nuclei.