What is a refract?

Answer 1

refraction is the bending of light or sound waves

But 'bending' is only a description of an apparent 'effect', not a mechanism.

Also; the 'causal wavefront' is not 'bent' in refraction, because refraction is a measure of the change of apparent source position to any detector (observer).

As we know from 'kinetic reverse refraction' and 'Invisibility optics', the axis of re-emission of em waves (including in the visible range) gives the apparrant source position, which may be rotated AWAY FROM the wavefront of the original emission.

We may then follow the 'rotation by means of Huygens Construction (the Huygens Fresnel Principle of continuous spontaneous localisation via absorption and 'coherent forward scattering' by each electron (molecules scatter light 'all round). Which may be characterised as 'wavelets' interfering with each other, constructively or destructively.

This is very poorly understood outside the specialist areas of science that deal with it.

And nobody has yet resolved the fundamental question 'what is waving'. Or 'what is the dark energy that we believe comprises 73% of the mass energy of the universe.