1590s, "open assembly place, chief public square and marketplace of a town; popular political assembly held in such a place," from Greek agora "an assembly of the People" (as opposed to a council of Chiefs); "the place of assembly; a marketplace" (the typical spot for such an assembly), from ageirein "to assemble," from PIE root *ger- "to gather." The Greek word also could mean "public speaking," and "things to be sold." For sense, compare Roman forum.