The dictionary definition of a polymath is a very learned person, of encyclopedic knowledge.

[polymath22]

http://www.angelfire.com/fl/polymathsociety/whatis.html


There is also the connotation of having an understanding deeper than that found in an encyclopedia, that is, an expert in many fields.

Anyone can be a polymath as long as he or she has the right motivation. A polymath is not necessarily a brain. In fact, a polymath usually does not think of his or herself as being particularly smart, only curious.