The book of Exodus tells about God giving Moses the Ten Commandments. Moses also recounts this event later on in Deuteronomy, listing the same Ten Commandments. He says God gave him those laws, wrote them on two stone tablets, and added nothing more. He says after he broke those tablets and had to get new ones, the same list of laws was written on the new tablets. And he refers to the laws that were written on the tablets as the Ten Commandments. The list of laws goes something like this:

1. Don’t worship other gods.
2. Don’t make images.
3. Don’t misuse God’s name.
4. Don’t work on the Sabbath.
5. Honor your parents.
6. Don’t murder.
7. Don’t commit adultery.
8. Don’t steal.
9. Don’t give false testimony.
10. Don’t covet.

But in Exodus, when God gives Moses the laws to write on the new set of tablets, they’re not the same laws that were on the first ones, despite what Moses claims. God gives him an almost completely different set of laws, and these too are referred to as the Ten Commandments. The new list of laws goes something like this:

1. Don’t make a treaty with the natives.
2. Don’t make idols.
3. Celebrate the Festival of Unleavened Bread.
4. Give every firstborn to God.
5. Don’t work on the Sabbath.
6. Celebrate the Festival of Weeks and the Festival of Ingathering.
7. Appear before God three times a year.
8. Don’t sacrifice anything with yeast or leave any Passover sacrifices till morning.
9. Give God the best of your firstfruits.
10. Don’t cook a young goat in its mother’s milk.

These laws are also mentioned elsewhere in Exodus (after Moses gets the first set of tablets and before he gets the second set of tablets). But that time they’re not called the Ten Commandments, and they’re not even all grouped together. They’re mixed in with a bunch of other rules, rather than being presented as anything special. But then after Moses destroys the original tablets with the Ten commandments, suddenly these random rules are the Ten Commandments instead?