Juli Clover, writing for MacRumors:
It’s a change that appears to have started rolling out with the launch of the newer Apple Stores, like the Union Square location in San Francisco. Apple has always referred to that store as just Apple Union Square, and over the course of the last few days, the company has updated all of its retail store webpages to remove the “Store” branding. What was once “Apple Store, Fifth Avenue,” for example, is now just “Apple Fifth Avenue.”
This seems to fall in line with Apple’s online store overhaul that took place around this time last year. I don’t think Apple wants to emphasize the shopping aspect in their branding anymore, instead focusing on helping customers learn about the products.