What's a corner store? asks trump during his latest "weave" [View all]

Apparently, while he was talking to workers in Las Vegas he read a speech including the words corner store. He then claimed not to know what it was and berated the speechwriter who wrote it for him.

Now I'm a Californian and never use that term. But if you had asked me yesterday I would have had a workable idea of what it was. Also, isn't it a NEW YORK CITY thing? And didn't trump grow up in NYC?
So what the h double hockey sticks is going on here?