Entry has loads of meanings, most of them concerning going inside someplace and the way you happen to get inside. It can also refer to written records (as in a diary or ledger) or a submission to a contest.
When you go into the room, you make an entry. The door you go through is also an entry. If you write in your diary about all this, you make an entry in your diary. If you submit your diary page to the "Awesome Writer" writing contest, your submission is also called an entry. And, finally, if you keep a spreadsheet for all your writing contest submissions, don't forget to make an entry (for this entry about an entry via an entry).