To Ring
intransitive verb, godan verb
This is a lot like 鳴く, which means "to chirp" (or some other animal noise). This has to do with noises too, but not so much animal and more like bells (including telephones). This word means to ring. If it helps, think of the る as a hint, kind of like the first sound of the word "ring" (る). So, る = "ring" and it's a verb, so to ring.
The reading can come from 鳴く. So long as you know the reading for that word you can know the reading for this word as well.
アラームが鳴る
the alarm goes off
音が鳴る
a sound is emitted
電話が鳴る
the telephone rings
お腹が鳴ってしまった。
My stomach growled.
だれかの電話が鳴ってるね。
Somebody's phone is ringing.
雷が鳴ったが、雨は降らなかった。
Thunder rumbled but it didn’t rain.