Many libraries use Library of Congress Subject Headings (LCSH), which are maintained by the Library of Congress, in bibliographic records to help organize items that are similar in subject. It creates a shared vocabulary among libraries, helping users discover more sources related to a particular topic.
Keep in mind, though, that this shared vocabulary is approved by Congress and is a product of society, based within a historically white profession and culture. Librarians are also involved in social justice work and seek to disband antiquated and offensive terms, though not always approved by Congress. For example, efforts to change the subject heading illegal alien to noncitizen and unauthorized immigration were not approved by Congress. (See the 2016 Library Journal article "Library of Congress Drops Illegal Alien Subject Heading, Provokes Backlash Legislation.")