These words have numerous distinct uses separate from each other, but they share the meaning of an establishment where merchandise is sold, usually on a retail basis. Store is a more general term, shop being reserved for a small store or for a department in a large store selling a select or special type of goods. One refers to a department store or grocery store and to a shop that sells hats or gloves or china or other specialized wares. Again, one might mention a shoe store but would refer to a shoe repair shop.
Dictionary of problem words and expressions. Harry Shaw. 1975.