noun ther·mo·sphere \ˈthər-mə-ˌsfir\

Definition of thermosphere

  1. :  the part of the earth's atmosphere that begins at about 50 miles (80 kilometers) above the earth's surface, extends to outer space, and is characterized by steadily increasing temperature with height


play \ˌthər-mə-ˈsfir-ik, -ˈsfer-\ adjective

Origin and Etymology of thermosphere

International Scientific Vocabulary

First Known Use: circa 1950

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