- The rigid, calcareous material that is white in color and forms the skeleton of vertebrates; primarily composed of calcium hydroxyapatite with smaller amounts of calcium carbonate, calcium fluoride, magnesium phosphate, and ossein, a high molecular weight protein. Bones have a concentric structure with central lymphatic canals surrounded by a spongy lamellar region protected by a dense outer cortex. Bone has been carved and used since ancient times for many purposes, including fish-hooks, spear heads, needles, handles, and art objects. Bones were also burnt to produce bone black and boiled to produce bone glue. Bone can be distinguished from ivory by being generally whiter, more porous, and less dense.
- Typically reserved to refer narrowly to the cultures of the native peoples of the United States and Canada, excluding the Eskimos and Aleuts. For the indigenous peoples of Canada use the term "First Nations." For the broader concept of the cultures of any native peoples of Central America, South America, North America, or the West Indies who are considered to belong to the Mongoloid division of the human species, use "Amerindian (culture)."
- Refers to the cultures of the continent of North America, which is bounded by the Atlantic Ocean, the Pacific Ocean, the Arctic Circle, and Central America. In classifications schemes based on physical geography, Central America, and North America are parts of the same continent.