IMHO, using "ordered dictionaries" references is somewhat confusing now that dictionaries preserve insertion order.

PR changes this references to "OrderedDict object".

"ordered dictionary" means "dict-like object which preserves insertion order".  Both of dict and OrderedDict is "ordered dictionary".

If we change it to OrderedDict, it make harder to change return type from OrderedDict to normal dict.

Do you propose we should never change return type?

Sometime, we chose weak name like "file-like" or "dictionary" over "io.TextIOWrapper" or "dict", to avoid making future improvements harder.

If there are no strong reason to specify concrete type, let's keep using weak name.

In case of enum members, I want to change it to regular dict in Python 3.8, but I'm not sure yet.

Please note that DictReader already mentions "OrderedDict" as a type it returns now. I do see the issue you raise though and I'm not proposing to guarantee that type for next versions.

I see the benefits of using weak names, but "dictionary" alone doesn't seem like a good weak name to me, as it's the common name of an actual type. "ordered dictionary" is the common name of a type, too, which makes the "dictionary" in that phrase less of a weak name. Bacause of this, I don't think we are using weak names in the cases the PR changes.

A dict-like object must preserve insertion order as that's what dict does; specifying it could make people think dicts aren't ordered. I understand a dict-like object as if it were a dict subclass, that is, following the full dict API.

As to what the changes could look like with these things in mind... It's difficult to say without knowing which API are we actually telling people to rely on now: dict, dict-like, OrderedDict, OrderedDict-like?

I believe the discussion in #33863 is relevant. Depending on what the API the user can rely on, perhaps "an ordered mapping" fits here too.

> Please note that DictReader already mentions "OrderedDict" as a type it returns now.

OK, but PR-7535 changes enum too.

> but "dictionary" alone doesn't seem like a good weak name to me, as it's the common name of an actual type.

As I commented in #33863, "dictionary" is really common weak name defined in glossary.  dict ∈ dictionary

Perhaps we can continue the discussion on #33863 as there are more argumnets there, from all points of view, and when a decision is taken there, we can apply it here too.

As I said on the PR:

This feels like an unnecessary change. The phrase "ordered dictionary" does not always refer to an 'OrderedDict`, and there is more than one way to order a dictionary besides insertion order.

As a side note: it's generally better to have different pull requests for different modules.