A digit is any single number from 0 through 9. The number 7 is one digit, while 47 has two digits (a 4 and a 7), and 582 has three digits. When you write any number, you're combining digits, just like combining letters to make words.

The word comes from the Latin word for finger, digitus, because people have counted on their fingers for thousands of years. You have ten fingers, and we use ten digits in our number system.

Digit can also mean a finger or toe, though this use is less common today. A doctor might refer to your digits when examining your hands or feet. Some animals, like raccoons, have especially nimble digits that help them grasp objects, almost like having hands.

When someone talks about a three-digit number, they mean any number from 100 to 999. Single-digit numbers are just 0 through 9, while double-digit numbers run from 10 to 99. Understanding how digits work together helps explain why our number system is so powerful: you can write any number imaginable using just ten basic symbols.