Wiktionary
n. The building containing the physical goods sold by the dot.com operations of a supermarket.
Wikipedia
The term dark store, dark supermarket or dotcom centre refers to a retail outlet or distribution centre that caters exclusively for online shopping. A dark store is generally a large warehouse that can either be used to facilitate a "click-and-collect" service whereby a customer collects an item they have ordered online, or as an order fulfilment platform for online sales. The format was initiated in the United Kingdom, and its popularity has also spread to France followed by rest of European Union.
Usage examples of "dark store".
He went on to the Gashwiler Emporium and let himself into the dark store.
Sugar picked his way through the dark store, and the door keeper let him out into the street.
LuEllen shut the door, grabbed the front of my shirt, and led me down the aisles of the dark store, all the way to the back.