To Close
To Shut
intransitive verb, godan verb
If 閉める is "to close something" or "to shut something," then this is going to be the version where you don't do anything and something closes on its own. That's why this is to close or to shut. You remember this because the door keeps shutting on your hand, marring (まる) it over and over again. Ouch.
The reading is the same as 閉める.
ドアが閉まる
the door closes
店が閉まる
the shop closes
シャッターが閉まる
the shutter closes
フタが閉まる
the lid closes
カギが閉まる
the lock locks
このフタ、うまく閉まらないんだけど。
This lid doesn't close properly.
あのお店、何時に閉まるんだっけ？
What time was it that the store closes?
急に、とびらがひとりでに閉まりました。
Suddenly, the door closed by itself.
げ、カギが閉まってる！
Shoot, it's locked!