Exactly. One describes a type, the other a numberer. Very different concepts, even if the latter is often used in the implementation of the former (e.g. in Pascal and Rust). Glad to see you are past your earlier confusion.
There are innumerable ways you can rectify this lack of understanding if you want to.
1. If you have a pet sum type definition, let it be known. But traditionally, a sum type is better known as a discriminated or tagged union. So far, this is what we understand Pascal offers: A union type that discriminates its subtypes by an enumerated value.
2. The tag that discriminates the type within the union (or whatever your explanation above ends ups calling it) is, in implementation, generated by a process that assigns a number to each entity; something also true of Rust. This is undeniable, as proven by the use of Ord and mem::discriminant. If you have another name for that numberer, if not an enumerator, let it be known.