Part of speech: Noun
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
The word "cyclopaedia" comes from Ancient Greek κύκλος.
cycle – A related word in the same word family.
encyclopedia – A related word in the same word family.
Greek roots often combine to create compound words with very specific meanings in science and medicine.