I personally think many people don’t really understand the scope of enterprise apps. They think of it as a narrow field of supplying apps for use by employees. Most of the projects I have worked on over the last few years have been enterprise rather than consumer focussed and none of them have been for use by employees.
If you think of enterprise as apps being being sold to enterprises rather than consumers you can probably imagine more business areas. Also think about the use of apps by an enterprises’ suppliers and customers. These can be other businesses or actually end consumers.
Wikipedia says an enterprise can be "Any organization, including businesses, non-profits, and government agencies". This opens things up further to areas such as education, health, government and charities. Enterprise apps tend to have longer lifetimes and hence tend to get updated more. They can also often be white labelled or branded to sell the same thing many times.