"person of various learning," 1620s, from Greek polymathēs "having learned much, knowing much," from polys "much" (from PIE root *pele- (1) "to fill") + root of manthanein "to learn" (from PIE root *mendh- "to learn"). Related: Polymathy "acquaintance with many branches of learning" (1640s, from Greek polymathia "much learning"); polymathic.
polygraph
polygyny
polyhedral
polyhedron
polyhistor
polymath
polymer
polymerase
polymeric
polymerism
polymerization