What about libraries and BISAC headings? See the links at the end of this post.
The BISAC Subject Headings List, also known as the BISAC Subject Codes List, is a standard used by many companies throughout the supply chain to categorize books based on topical content. The Subject Heading applied to a book can determine where the work is shelved in a brick and mortar store or the genre(s) under which it can be searched for in an internal database.
The complete BISAC Subject Headings List is available online at no cost for one-to-one look-up. You may also request an End Users’ License to download versions of the Subject Headings List in Excel, PDF and Word for incorporation in your company’s internal databases.
The BISAC Subject Headings List is governed by the following copyright notice:
Copyright 2011, Book Industry Study Group, Inc.
All rights reserved. No part of the BISAC Subject Headings List documentation may be distributed or reproduced in any manner whatsoever without the express permission of the Book Industry Study Group, Inc.