A meaning of a term is determined using the contents of a corpus of books through use of metadata about the books within the corpus, terms in the same work which provide context, and so forth. Users may query to determine the meaning of a term. Users may also build vocabulary skills by testing as well. A changing meaning of a term over time may be determined and utilized as well. Searches are facilitated by the enhanced ability to determine meaning of the terms, particularly in context. Feedback from the searches may also be used to refine future searches.