Definition of E-layer in English:

E-layer

noun

  • A layer of the ionosphere able to reflect medium-frequency radio waves.

    • ‘The effect of the Ampére force on inertio-gravity (IG) waves in the partially ionized ionospheric E-layer is considered.’
    • ‘At the fully-developed stage, the fully-extended luminous body connected the cloud top at 15km with the E-layer ionosphere at 90km.’

Origin

1930s: arbitrary use of the letter E, + layer.