>>512551531
Well a pregnancy test is a computer, a server is a computer, a calculator is a computer, a router is a computer, a pic microcontroller is a computer.
My answer could be:
"A Turing complete structure, preferably with I/O."
But then maybe this isn't the correct answer because now I have to define what Turing complete means and I'm suspecting that you want the sentence to be free of dependencies.
Furthermore there are computers that are specialized enough that are not Turing complete, that do not have I/O, but the structure is there.
>"A computer is a turing complete, or Turing approximate structure/implementation of formal logic that can perform logical/mathematical manipulations on stored or provided data by following instructions stored at a memory address (Like the eip)"
> Joke answer: a computer is anything that can run Doom.

Nah... That still doesn't sound right.
Can you give me a hint?

I want to provide an answer following Leibniz's law.
To reduce the idea to its essentials...