We’re primarily “customer” but I’m hoping someday to get to “owner.” one of the coolest things in the credit union industry was one CU that had signs in their parking lot “owner parking only.” really hammered home for CU members that they owned the organization. while there’s probably some debate, for a publicly funded institution, aren’t all tax paying residents owners of the library in part?
We use the term "Client" to refer to our users.
Some years ago, we actually asked people what they wanted to be called. They vote overwhelmingly for 'patron', though I wonder what people would say now.