A part number is like a name for something that is made in a factory, like a toy or a machine part. Just like how you have a name to identify yourself, a part number is used to identify these things. It's like a special code that only the people who work in the factory can understand. When someone needs to order a specific part, they use the part number to make sure they are getting the right thing. Think of it like a secret code for things that are made in a factory!