Subject terms can sometimes be a more accurate and comprehensive way of searching for a topic than keyword searching. Subject terms can be found on the left-hand column of search results in the catalog, or at the end of a book's catalog entry.
Some sample subject terms, for instance:
The Oxford English Dictionary, or OED as it's more popularly known, is a historical dictionary of English, covering the language from the earliest times to the present day. It aims to show not only the current meanings of words, but also to trace their development through time. Entries contain detailed etymological analysis, and are illustrated by quotations from a wide range of English language sources from around the world, making the OED a unique historical record. Available in print and in electronic version.
Corpus linguistics is a method of linguistic research that uses corpora, or large databases of text, to analyze language use.