A "belter" can have different meanings depending on the context. Here are some definitions from the search results:

• A singer with a powerful voice.
• A rousing or spirited popular song that is sung.
• Anything that is particularly good of its class.
• A very good example of something.
• A person who mines asteroids for minerals or lives in the vicinity of an asteroid belt (science fiction) .

In summary, "belter" can refer to a singer with a powerful voice, a rousing song, something that is particularly good, or a person who mines asteroids in science fiction.