Shockwave, Aftershock & Explosion

Shockwave, Aftershock & Explosion. How each one works exatacly in the game mechanics?
There is any difference?

Aftershock is a keyword, so has a specific definition: "burst of area damage that occur after the initial impact of the skill causing them. If not otherwise specified, the Aftershock will deal the same damage as the initial impact, in the same area".

Shockwave and explosion are used in their common meaning to indicate damaging AoEs.

thank u a lot!