Karma is a sanskrit term going back at least to Vendanta philosophy texts a few thousand years old, predated even Hinduism.
It’s a word used to identify an observable phenomenon that exists. It’s basically the same as the physics principle that for any action there is a reaction… i.e. if you do something, something happens.
The relative newcomer, the Judeo-Christian Bible, says you reap what you sow, same thing.
In neither case is it a matter of some entity that is keeping the books and will be out to get you if you misbehave.
It’s a matter of the fact that actions have consequences, as we try to teach kids. The universe as we know it simply causes this. For the kids the parents are likely to be imposing the consequences, but in general society at large will do that, too.
If you plant trees a forest will grow. If you burn trees down you get smoke.
It’s not at all confined to “getting even” although it’s almost always brought up that way in current pop usage. It’s the same as “hard work pays off” “a stitch in time saves nine” and the Golden Rule to treat others as you would like to be treated.
Genius is 99% perspiration and 1% inspiration;
[ or Tad Friend “Luck is the residue of design and devotion” New Yorker Sept 16, 2013 ]
Awareness of the idea of karma, that life is not consequence-free, and that one ought to pay attention to one’s actions even if only for purely selfish reasons, does seem to be a principle embraced by all religions and philosophies.