Someone who owns a business or a property is a proprietor. A bookstore proprietor might wish she became a librarian instead so the books would come back.
The first part of proprietor sounds a lot like "property," and a proprietor is someone with ownership of property. Sometimes a proprietor oversees the business, such as a restaurant proprietor who is also a chef or hostess, and other times a proprietor owns many businesses and has different people running them. A proprietor of a local bakery might make and sell his own donuts, while the proprietor of a chain of donut shops might work from an office managing the people who manage the stores.