The term "booming" has several meanings depending on its context.
1) Booming can refer to a loud, deep sound such as that made by thunder or a large drum. For example, "the booming noise startled everyone."
2) It can also be used to describe something that is growing rapidly and expanding in popularity. An example of this usage would be: "The craft brewing industry has been experiencing a boom over the past few years."
3) In some financial contexts, "booming" refers to an economy or market that is experiencing rapid growth and expansion. For instance, "the stock market was booming during that time period."