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.
Mount Rainier is the highest volcanic peak in the Cascades, a mountain range that stretches from Mount Garibaldi in British Columbia to Lassen Peak in Northern California. Mount Rainier was formed not in one great cataclysm, but by many years of volcanic activity. It is a composite volcano (or stratovolcano) made from sluggish, intermittent lava flows and explosive eruptions of ash and rock. Volcanoes have been erupting in this region for at least 40 million years.