system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: an electron has a 'negative' charge and a proton a 'positive' charge, but what exactly is a 'charge'.

And , if a neutron has no charge,  what is it then?
gpt
Ultimately charge is just a name we have given to a property we have discovered.  We have learned how different values of that property interact with each other and used that to devise a theory that explains their behavior.

Asking what it "is" is like asking what blue is, and why we call that color blue and this one red, and not the other way around.  There's not a satisfying reason, it's just because those are the names we've chosen to describe the properties.