I live in NY now so I might be able to help. The supermarkets sell what they call 'all purpose' flour. I have only found one shop that sells self-raising, I haven't seen plain anywhere. Similar with sugar, they seem to have a 'general' sugar to cover all jobs and don't even get me started on the 'confectionary' sugar which is meant to be similar to icing sugar! All guests now have to bring some silver spoon with them
So in answer to your question, I guess they mean 'all purpose' flour but I don't know enough about baking to suggest what you should use. HTH.