D region

noun

Definition of D region

: the lowest part of the ionosphere occurring approximately between 30 and 55 miles (50 and 90 kilometers) above the surface of the earth

First Known Use of D region

1930, in the meaning defined above

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The first known use of D region was in 1930

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Cite this Entry

“D region.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/D%20region. Accessed 7 Jul. 2020.

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