D layer

D layer

noun
the lowest region of the ionosphere, characterized by mounting electron and ion density: exists, during the day only, from about 43 to 50 miles (70 to 80 km) altitude.
Compare D region.


Origin:
1930–35

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Collins
World English Dictionary
D region or D layer
 
n
See also ionosphere the lowest region of the ionosphere, extending from a height of about 60 kilometres to about 90 kilometres: contains a low concentration of free electrons and reflects low-frequency radio waves
 
D layer or D layer
 
n

Collins English Dictionary - Complete & Unabridged 10th Edition
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American Heritage
Science Dictionary
D layer  
See D region.
The American Heritage® Science Dictionary
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