The story
Originates from the layouts of budget supermarkets Aldi and Lidl, in which part of a central aisle is dedicated to bargain home goods.
Etymology from Wiktionary, CC BY-SA 4.0.
middle aisle
Today it means: Part of a supermarket which sells a regularly-changing range of nongrocery products, such as tools, household appliances and clothing, at low prices. Full definition →