Subject encyclopedias are much more than a way of picking up quick facts. Typically put together by scholars and other experts in the field, they can provide an overview of a field or fill in topics for unfamiliar areas of research. The articles usually also include a list of important books and articles. Not a substitute for research but a quick way of getting you started.
Although we have no comprehensive online encyclopedias that focus on the entire field of Communication, the listings below include the International Encyclopedia of the Social and Behavioral Sciences, which has more than 100 articles on media lone. Several take on different areas of Communication. And we do have three 21st century encyclopedias, existing only in print, covering the broad scope of the discipline. These are in the SSHL Reference collection (main floor of Geisel Library)