East-West (Dong Xi 東西) means “things” in everyday life usage of the term.
To buy something is Mai Dong Xi 買東西.
But why East-West and not North-South?
Here is a story explaining why.
Song Dynasty scholar Zhu Xi 朱熹 met his friend on the street. He asked his friend where he was heading. His friend said, “I am going to buy East-West.”
Zhu Xi asked, “Why buy East-West and not South-North?”
His friend replied, “You see? The basket I am carrying is made of bamboo. The south is fire while the north is water. Fire will burn my basket while water will leak out. Therefore, I cannot buy South-North. The east is wood while the west is metal. They can be put in my basket. That is why I am buying East-West and not South-North.”