"public square or open space surrounded by houses," originally in a Spanish or Spanish-American town or city, 1830, from Spanish plaza "square, place," from Vulgar Latin *plattia, from Latin platea "courtyard, broad street" (from PIE root *plat- "to spread").
also *pletə-, Proto-Indo-European root meaning "to spread;" extension of root *pele- (2) "flat; to spread."
It forms all or part of: clan; flan; flat (adj.) "without curvature or projection;" flat (n.) "a story of a house;" flatter (v.); flounder (n.) "flatfish;" implant; piazza; place; plaice; plane; (n.4) type of tree; plant; plantain (n.2); plantar; plantation; plantigrade; plat; plate; plateau; platen; platform; platinum; platitude; Platonic; Plattdeutsch; platter; platypus; plaza; supplant; transplant.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit prathati "spreads out;" Hittite palhi "broad;" Greek platys "broad, flat;" Latin planta "sole of the foot;" Lithuanian platus "broad;" German Fladen "flat cake;" Old Norse flatr "flat;" Old English flet "floor, dwelling;" Old Irish lethan "broad."
c. 1400, "wooden siege tower on wheels" (late 13c. in Anglo-Latin with a sense "bell tower"), from Old North French berfroi "movable siege tower" (Modern French beffroi), from Middle High German bercfrit "protecting shelter," from Proto-Germanic compound *berg-frithu, literally "high place of security," or that which watches over peace." From bergen "to protect" (from PIE root *bhergh- (1) "to hide, protect") or [Watkins] *bergaz "mountain, high place" (from PIE root *bhergh- (2) "high," with derivatives referring to hills and hill-forts) + *frithu- "peace; personal security" (see affray).
The etymological meaning was forgotten, which led to folk-etymologies and a great diversity of spellings. It came to be used for bell towers (mid-15c.), which at first often were detached from church buildings (as the "Leaning Tower" of Pisa and the Campanile on Plaza San Marco in Venice), and the spelling was altered by dissimilation or by association with bell (n.).
c. 1200, "space, dimensional extent, room, area," from Old French place "place, spot" (12c.) and directly from Medieval Latin placea "place, spot," from Latin platea "courtyard, open space; broad way, avenue," from Greek plateia (hodos) "broad (way)," fem. of platys "broad," from PIE root *plat- "to spread."
Replaced Old English stow and stede. From mid-13c. as "particular part of space, extent, definite location, spot, site;" from early 14c. as "position or place occupied by custom, etc.; precedence, priority in rank or dignity; social status, position on some social scale;" from late 14c. as "inhabited place, town, country," also "place on the surface of something, portion of something, part." Meaning "a situation, appointment, or employment" is by 1550s. Meaning "group of houses in a town" is from 1580s.
Also from the same Latin source are Italian piazza, Catalan plassa, Spanish plaza, Middle Dutch plaetse, Dutch plaats, German Platz, Danish plads, Norwegian plass. The word appears via the Bible in Old English (Old Northumbrian plaece, plaetse "an open place in a city"), but the modern word is a reborrowing.
Sense of "a mansion with its adjoining grounds" is from mid-14c.; that of "building or part of a building set apart for some purpose is by late 15c. (in place of worship). Meaning "a broad way, square, or open space in a city or town," often having some particular use or character (Park Place, Waverly Place,Rillington Place) is by 1690s, from a sense in French. Its wide application in English covers meanings that in French require three words: place, lieu, and endroit. Cognate Italian piazza and Spanish plaza retain more of the etymological sense.
To take place "happen, come to pass, be accomplished" (mid-15c., earlier have place, late 14c.), translates French avoir lieu. To know (one's) place "know how to behave in a manner befitting one's rank, situation, etc." is from c. 1600, from the "social status" sense; hence the figurative expression put (someone) in his or her place (1855). In in the first place, etc., it has the sense of "point or degree in order of proceeding" (1630s). Out of place "not properly adjusted or placed in relation to other things" is by 1520s. All over the place "in disorder" is attested from 1923.
word-forming element which in English is characteristic of fem. nouns and adjectives of Latin or Greek origin (such as idea, coma, mania, basilica, arena, formula, nebula). From Latin -a (plural -ae) and Greek -a, -ē (plural -ai, Latinized as -ae). The Latin suffix also became Italian -a (plural -e), Spanish -a (plural -as). It is represented in Old English by -u, -e, but even then the suffix was fading and by the time of modern English was totally lost or swallowed into silent final -e-.
It also appears in Romanic words from Latin that have been borrowed into English, such as opera, plaza, armada. It figures in scientific names coined in Modern Latin (amoeba, soda, magnolia, etc.) and is common in geographical names formed according to Latin or Greek models (Asia, Africa, America, Arabia, Florida, etc.)
In English it marks sex only in personal names (Julia, Maria, Alberta) and in a few words from Italian or Spanish where a corresponding male form also is in use (donna, senora).