Is it worse than calling your auto-resizing-sequence type "vector", even though a vector is properly a tuple of (arbitrary) fixed size, and is incomparable with another thing of any other size?

(okay, I guess it might be worse than that)

Yes, because vector is a library, not part of the core language itself.

Well, not just some library. (The 'standard library' should be seen as part of the language.)

True, but there is a huge difference between a standard library feature and a keyword.

Not really... Not in the case of the standard library anyway.

A keyword is a more core part of the language than the standard library. I could re-implement my own vector. I cannot add my own keyword.

No, you cannot/wouldn't reimplement std::vector (not in the sense you are implying).

Compiler writers often extend the language with new keywords.

Can you elaborate on the last point? Do you mean things like macros they use, e.g., concepts lite, or __builtin* functions?

I still feel like a standard container is less fundamental than keywords, but I value your perspective.

Yes, built-ins, intrinsics, and extensions.

My original point was simply that std::vector, say, is just as good a "keyword" as any - perhaps, not because you cannot redefine it but because you wouldn't, and if you didn't like what it does, you'd use/implement something else.

Applicative is actually a lying name as it has little to do with Applicative category in maths. (an Arrow does, is a subkind of mathematical applicatives)

It is in the same category of lies like C++ calling its thing a class. (except C++ does not try to have math background)

I prefer a common name to a wrong and confusing name.

How is a C++ not a class? It’s a class of objects satisfying certain operations and possessing certain attributes.

As a teen, I was introduced to C++ by a friend (who was trying to get me to stop programming in BASIC). We had a serious bit of confusion for a moment when I couldn't understand where he was watching/attending/accessing these "classes".

Imagine how much more fun we could have had if they had "concepts" in the language back then!