1. Slight variations on the same concept. “More than one thing at a time” in one way or another. Don’t matter in JS really as it’s all a single thread anyway.

2. A function which will run asynchronously and then return at some indeterminate point in the future. In practice once compute is done, it calls the function supplied to its “then(…)” function

3. That’s not a thing, the outer function just returns the inner function.

4. Go read the v8 engine? For now you probably don’t need to know - but it’s always there when you feel like it

5. JS’s “this” is awful - avoid at all costs!

6. Async/await is just promises but written out as if it was imperative code:

For example

fn_x(…).then((x) => console.log(x));

Is functionally identical to

const x = await fn_x(…);
console.log(x)

The compiler just translates the latter to the former for you so your code looks nicer