polymath \POLL-ee-math\, noun: A person of great or varied learning; one acquainted with various subjects of study.
A century after Aristotle, in 240 B.C., a brilliant polymath, Eratosthenes, is appointed chief librarian of the Museum at Alexandria--the most cosmopolitan city and center of learning in the Mediterranean world. --Alan Gurney, Below the Convergence
Alan Kay, for instance, one of the wizards of PARC and now an Apple fellow, is a polymath accomplished in math, biology, music, developmental psychology, philosophy, and several other disciplines. --Warren Bennis and Patricia Ward Biederman, Organizing Genius: The Secrets of Creative Collaboration
[L]ike her literary heroine, George Eliot, Kingsolver is an old-fashioned polymath, curious about all branches of human learning. --"The Novel As Indictment," New York Times, October 11, 1998
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Polymath is from Greek polymathes, having learned much, from poly-, much + manthanein, to learn.