'Place,' 'plaza,' and 'piazza' are all from Greek 'platys' (broad, flat) — one concept, three languages.
A particular position, point, or area in space; a location or spot.
From Old French 'place' (open space, square, marketplace), from Medieval Latin 'placea,' an alteration of Latin 'platea' (broad street, open area in a city), itself borrowed from Greek 'plateîa' (πλατεῖα, broad street), the feminine of 'platýs' (πλατύς, broad, flat), from PIE *pleth₂- (to spread out, flat). The same PIE root gave English 'flat' through Proto-Germanic *flataz, 'plaza' through Spanish (which preserved the Latin more faithfully), 'plate' (a flat dish), 'platform' (flat form), and 'platypus' (flat-footed). Greek 'Plátōn' (Plato) was a nickname