Let’s refer to the Latin dictionary:
perfectus, perfecta, perfectum
Translation (definition): complete
It means that the Present Perfect denotes a completed action (or a completed inaction, yes, it sounds weird, but a “completed inaction” means that an action didn’t start at all and, of course, it wasn’t completed, which is usually expressed by a negative construction). You can even say Present Completed, or if it’s a negative sentence, you could say “Present Uncompleted” 🙂 thought they are not the official names, remember, all tense names presume a positive sentence and an action (vs inaction) as a basis in the naming convention:
She hasn’t done it yet.
The fact that it’s a negative sentence doesn’t make the name of the tense “Present Imperfect” 🙂
A few more examples expressing completeness of an action:
What have you learned so far / by now?
Have you already completed your homework?
He has already mailed her back
In a nutshell (exceptions may apply)
We use Present Perfect when we have something that shows us completeness of an action (“Perfect” means complete):
so far / by now, already, yet
More on Present Perfect: