An encyclopedia is a book or set of books in which facts about many different subjects or about one particular subject are arranged for reference, usually in alphabetical order.
英汉词典释义
n.
百科全书; (某一学科的)专科全书
I bought the encyclopedia on a whim.我凭一时的兴致买了这本百科全书。
英英词典释义
Noun
1. a reference work (often in several volumes) containing articles on various topics (often arranged in alphabetical order) dealing with the entire range of human knowledge or with some particular specialty