Don't make this more complicated than it has to be... "Customer Experience" is just what it says... the experience a customer has when dealing with your business. The means, from the initial contact, whether browsing in a store or on a web page, to the inquiries made regarding product or service, to the actual purchase of product or service, to the post-sale follow-up. Each interaction between a customer and your business amount to what Jan Carlzon called "Moments of Truth" in his excellent book by the same name.
The reason you can not find a usable definition of the term throughout your academic experience is because customer experience is not defined by academics, or even by know-it-all consultants like myself ;~)
The customer experience is defined, each and every time, by the customer. And one customer's definition is going to be different from the next. That is why my definition of The Golden Rule of Customer Service is not "Treat each customer the way you, yourself, wish to be treated," but rather "Treat each customer the way that THEY wish to be treated."
I hope this helps a little bit...