exobase

 

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exobase

Wikipedia

From exo- +‎ base.

exobase (plural exobases)

1. The base altitude of the exosphere, where particles often escape the atmosphere as it blends into space.

The exobase is commonly treated as the top of the conventional atmosphere of thick atmospheres. A more complex definition would be the top of the neutral atmosphere.

• exopause
• critical altitude