Okay kiddo, let me explain this to you in a very simple way. Some companies make and sell weapons like guns, bombs, and missiles. They make a lot of money by selling these weapons to governments or other countries. This is called arms sales.
These companies are in the business of making and selling weapons. Just like how a toy company makes and sells toys, these companies make and sell weapons. But sometimes, people have concerns about these companies because they worry about the harm that these weapons can cause.
So, to summarize: some companies make and sell weapons, and this is called arms sales.