The first discussion of flattening had to do with a list of data being
flattened into an array.
Further down we see another different use of the word "flattening" :
The unary prefix operator * flattens its operand (which allows the
elements of an array or iterator to be used as an argument list).
Here I understand this to mean that the array is spreading or
distributing its elements to individual scalars.
So, to avoid confusion with the common understanding of flattening in
Perl, perhaps it should be called spreading or distributing.