There are no good names for them, and users never need to think about them really. It's just a simple
```
If a byte starts with 0b110, char is 2 bytes.
If a byte starts with 0b1110, char is 3 bytes
If a byte starts with 0b11110, char is 4 bytes
etc
```
I think it would probably be more confusing to give them long names, especially since a user does not need to worry about it.