Tertiary sources compile, summarize, index, or help identify scholarly sources on a topic. They are useful for background research or to get an overview of a topic before delving into secondary or primary sources. Common tertiary sources for modern languages include dictionaries, encyclopedias, handbooks, and other reference sources.
From this page you can
The OED online can be used to perform simple searches for word definitions, or for full-text searching of all OED's definitions, etymologies and quotations through the Search function.
Biographical and critical essays on the lives, works, and careers of influential literary figures.
