I was in the central library a year or two ago, and I had to ask directions to the stacks, because the shelves were all being rearranged (downsized) and none of the diagram handouts matched the floor plan anymore.

Strolling down the aisle with the reference librarian, I asked about biographies and she said something like "the person that the book is written about" and I said "...Subject?" and she reluctantly admitted that most of the library patrons haven't learned library terminology, so the staff uses simple English to explain stuff to patrons.