Definition of atom. 1  1a : the smallest particle of an element that can exist either alone or in combination an atom of hydrogenb : the atom considered as a source of vast potential constructive or destructive energy â¦ a largely forgotten legacy of this country's conquest of the atom.
The mountain, a part of the Cascade Range, is a volcano that has not erupted for 2,000 years. It is also the highest mountain in the state of Washington. English explorer George Vancouver named Mount Rainier in honor of another navigator, Peter Rainier. Some people, however, prefer to call the mountain by its Indian name, Mount Tacoma.
Sponsored Topics. Rainier is a city in Thurston County, Washington, United States. Beginning as a train stop in the 1870s, Rainier was first settled in 1890, and was officially incorporated in 1947. The population was 1,794 at the 2010 U.S. Census.