Definition from Viima
“End-user is a person who ultimately uses a product or service. For example in software business, there's often a difference between the customer and the end user. The end user is the employee who uses the product whereas the customer is the one who makes the decisions to purchase the software.”
Going further
I've curated 400+ definitions just like this one in a tiny dictionary. In this glossary you can easily access, search and understand 400+ terms that service designers and other innovators use.