The most authoritative guide to Library of Congress (LC) terminology is the five-volume Library of Congress Subject Headings set shelved behind the Services Desk on the first floor of the library (call number READYREF Z695 .L695 25th ed.). These volumes indicate official LC subject headings and their relationships with other terms or headings: the official terms are Used For (UF) (for example, "Education," the official Library of Congress subject heading, is Used For (UF) "Children--Education"); the correct forms for headings (Use references); Broader Topics (BT); Related Topics (RT); and Narrower Topics (NT). In addition, the guide provides See Also (SA) notes concerning the use of a term as a subdivision of other headings (for example, "SA subdivision Study and teaching under subjects") and for other special cases.
Entries here in many cases also provide general Library of Congress call number ranges for particular subjects; for example, for Education--Philosophy, the LC classification parameters are given as LB 125-LB 875, and knowing this allows you to browse the stacks by call number, either physically or online through EDUCAT, to find books within this general subject area.
The online Library of Congress Authorities site allows you to browse and view authority headings for Subject, Name, Title, and Name/Title combinations, and here it is possible to search by "natural language" terminology (for example, "educational administration") and be directed, by clicking on the References tab, to the official terms in use, in this case "School management and organization" for K-12 administration, and "Universities and colleges--Administration" for higher education administration.