**Atomic Data** is the smallest unit of data that a computer program can define. The word “atomic” derives from the word “atom”. At one point in the history of chemistry, atoms were believed to be the smallest indivisible pieces of matter in the universe. In computer science, the word “atomic” is often used to refer to something that is indivisible or cannot be made smaller. By this, we don’t mean “smaller” in the mathematical sense; just because you can make the number 10 “smaller” by dividing it by 2 doesn’t mean that the value 10 isn’t an example of atomic data. Instead, we say “smaller” in the sense of simplicity. There’s no simpler way to express the number 10 than simply writing 10, so therefore it’s atomic.