piazza (n.)

1580s, "open public square in an Italian town," from Italian piazza, from Latin platea "courtyard, broad street," from Greek plateia (hodos) "broad (street)," from platys "broad, flat" (from PIE root *plat- "to spread"). 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 veranda of a house" (1724, chiefly American English).