For some reason, c++ folks seem to sometimes use "meow" as a placeholder. I thus guess that it means "all the something_n functions in <algorithm>", like http://www.cplusplus.com/reference/algorithm/fill_n/ ?
STL (Stephan T. Lavavej, that is, not the library) just happens to like kittens.
Yes. Why say "unordered_map, unordered_multimap, unordered_set, unordered_multiset" or the boring "unordered_foo" when I can say "unordered_meow", and so forth?
What do you use when you need more than one metasyntactic variable?