What is decimal money?

Could you please explain to me what exactly is meant by the term "decimal money"? I understand that it has something to do with the way money is valued and divided, but I'm not entirely clear on the specifics. How does it differ from other forms of currency, and why is it considered important in the world of finance and economics? Is it a new concept, or has it been around for a while? I'm eager to learn more about this topic and understand its significance in the modern financial landscape.