geometric shadow

geometric shadow

[¦jē·ə¦me·trik ′shad·ō]
(physics)
That region which a given type of radiation would not reach, because of the presence of an object, if the effects of diffraction and interference could be neglected.
References in periodicals archive ?
The Mount Teide volcano itself does not have the strictly pyramidal shape that its geometric shadow might suggest.
All at once, the vast space was cast into darkness, save for three small lamps illuminating the tables, while a wall of scrap cardboard transformed into an enormous landscape of geometric shadows and sunlit constellations, penetrating the gallery from outside.
Here at this moment, morning is most itself, Before the geometric shadows, more Substantial almost than what casts them, pale Into whatever later light will be.