1580s, "public square in an Italian town," from Italian piazza, from Latin platea "courtyard, broad street," from Greek plateia (hodos) "broad (street);" see place, n.. According to OED, mistakenly applied in English 1640s to the colonnade of Covent Garden, designed by Inigo Jones, rather than to the marketplace itself; hence "the verandah of a house" (1724, chiefly American English).