When Marquand was in McCormick Hall, there were many dictionaries of art terms and companions on art and art history in the reference room near the front entrance. Many of them had call numbers beginning with N33, so one could browse by call number in the library catalog.
Search the Grove Dictionary of Art (online: Oxford Art Online), or do a Subject (browse) search in the catalog. The latter takes practice, but can be very powerful – be as specific as possible. Library of Congress Subject Headings (used in the catalog), involve a string of terms and are “left-anchored,” so you can browse a particular topic by doing a search, and then examining all its subheadings, e.g. Photography or Archaeology (numerous sub-headings, by time period, by region, by theme). Subject Headings can be people, media (painting, sculpture), themes (Cubism), countries, specific artists (last name, first name), etc. A Subject (keyword) search allows you to search for keywords within a particular established subject term, which may also be a bit more precise than a regular keyword search.
Oxford Bibliographies is a tremendous resource for annotated bibliographies covering current scholarship that falls within a number of subject areas, Art History, being one of them. See the list of all topics covered under Art History here towards the bottom, along with forthcoming topics. See also Architecture Planning and Preservation section, or search for anything in the search box at upper right. Oxford University Press's series Very Short Introductions is also a useful set of print and online guides for learning about a field or topic. Click Browse by Topic at the upper left.
One can do the same thing with other general art historical (and related) series (look for individual titles in the library catalog, or search for the Series title in Advanced Search). Examples: Art & Ideas (Phaidon), A Closer Look (National Gallery, London); Critical Anthologies in Art & Culture (MIT Press); Dictionaries of Civilization; Documents of Contemporary Art (Whitechapel Gallery/MIT Press); Guide to Imagery (Getty); How to Read (Metropolitan Museum); Looking at ______: A Guide to Technical Terms (Getty); Object Lessons (Bloomsbury); Oxford History of Art; Pelican History of Art; Routledge Research in Architectural History; Routledge Research in Art History; Sources and Documents in the History of Art (or just look for subtitle "sources and documents"); and Wiley-Blackwell Companions to Art History.