An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

To disappear gradually.

→ vanish.

Tending to → vanish gradually.

Verbal adj. from → evanesce.

A wave whose → amplitude → decreases → exponentially with distance from the → interface at which it is formed. Evanescent waves are formed when → sinusoidal waves are internally reflected off an interface at an angle greater than the → critical angle so that → total internal reflection occurs.

→ evanescent; → wave.