Hi Kai, the phrase we use is 'roar of approval' and it refers to a group of people clapping or cheering when they like something or someone. For example, the winner of the game was greeted with a roar of approval when he entered the room. This means the people were clapping and cheering at the winner because they are happy that he won. Also, people are showing their approval - meaning they like or agree with something - when they are clapping and cheering. We use the word 'roar' because clapping and cheering make a loud noise, kind of like a roar. I hope this answers your question :)