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 extended spatial location of something; "the farming regions of France"; "religions in all parts of the world"; "regions of outer space"
a large indefinite location on the surface of the Earth; "penguins inhabit the polar regions"
the approximate amount of something (usually used prepositionally as in `in the region of'); "it was going to take in the region of two or three months to finish the job"; "the price is in the neighborhood of $100"