The term Encyclopedia comes from the Greek words εγκύκλιος παιδεία, enkyklios paideia ("in a circle of instruction"). From εγκύκλιος, circuit shaped from κύκλος circuit and παιδεία, meaning instruction. See the Note on spelling below.
Encyclopedias can be general, containing articles on topics in many different fields - the English language Encyclopædia Britannica and German Brockhaus are well-known examples, or they can specialize in a particular field (such as an encyclopedia of medicine or philosophy). There are also encyclopedias that cover a wide variety of topics from a particular cultural or national perspective, such as the Great Soviet Encyclopedia.