ELI5: Explain Like I'm 5

Ordinal number

Ordinal numbers are numbers that help us put things in order. They tell us the order of things, like first, second, third, fourth, etc. We can use them to count, like 1, 2, 3, 4, 5, and so on, but they also tell us what comes first and what comes second, like first prize, second prize, and so on.