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 action wasn’t completed, action just didn’t take place, which is usually expressed by a negative construction). If it makes sense to you , you can say Present Completed, or if it’s a negative sentence, you could say “Present Uncompleted” 🙂 thought the are not the official names, remember, all tense names presume a positive sentence and action (vs inaction):
She hasn’t done it yet. The fact that it’s a negative sentence doesn’t make the name of the tense “Present Imperfect” 🙂
What have you learnt so far / by now?
other examples expressing completeness:
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:
so far / by now, already, yet