ELI5: Explain Like I'm 5

Norm (mathematics)

Norm is a way of measuring how big something is. It's like a ruler for math. To measure a number, you use a norm to figure out how big it is. For example, if you have the number 5, it's bigger than the number 4. The norm for 5 is bigger than the norm for 4, so you know 5 is bigger.