Soon
Before Long, Shortly
adverb
The もなく part is like saying "there isn't even." So, when "there isn't even an interval of time," things will happen soon or before long.
You'll probably hear this the most in train announcements letting you know your train will shortly be arriving in Tokyo or wherever.
The reading for this one is weird, though. It's a second kun'yomi reading (there is also あいだ), read as ま. So what is happening soon? Your Ma is going to be here before long. You better hurry and prepare, because your room looks terrible...
"間もなく, your mom is about to show up!"
間もなくスタートする
will start soon
間もなくはじまる
to start soon
間もなく生まれる
will be born soon
間もなくオープンです！
It will be open soon!
教室のドアの音がしたので、間もなく先生が入ってくるかと思った。
I heard the classroom door, so I thought the teacher would come in soon.
間もなく朝ごはんが出来ますから、テーブルの上にスプーンとフォークを出して下さい。
Breakfast will be ready soon, so please put spoons and forks on the table.