Using many, numereous, several, multiple, various, some, a couple,...

[Pstein]

When do I use which of the following words:

Using many, numereous, several, multiple, various, some, a couple,....

Are there semantical differences?

If you have to sort them according to the number of things/items they represent:
Which order would you define?

Peter

[Haihao]

I would say there is semantical difference among them. And I'd sort them as: a couple of, several, many, numerous. Various is a different kind of word; some and multiple could modify a noun whose number, if any, can be from more than one to more than any.