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).
"a public address; a formal, vehement, or passionate address;" also "any formal or pompous speech; a declamation; a tirade," mid-15c., arang, Scottish (in English from c. 1600), from French harangue "a public address" (14c.), from Old Italian aringo "public square, platform; pulpit; arena," from a Germanic source such as Old High German hring "circle" (see ring (n.1)) on the notion of "circular gathering," with an -a- inserted to ease Romanic pronunciation of Germanic hr- (compare hamper (n.1)).
But Watkins and Barnhart suggest a Germanic compound, *harihring "circular gathering, assembly," literally "host-ring, army-ring," with first element *hari- "war-band, host" (see harry (v.)). From the same Germanic "ring" root via Romanic come rank (n.), range (v.), arrange.
1690s, from Late Latin tessellatus "made of small square stones or tiles," past participle of tesselare, from tessella "small square stone or tile," diminutive of tessera "a cube or square of stone or wood," perhaps from Greek tessera, neuter of tesseres, Ionic variant of tessares "the numeral four" (from PIE root *kwetwer- "four"), in reference to four corners. Related: Tessellate (v.), a 1791 back-formation (from 1826 as an adjective, 1909 as a noun); tessellating.
metric unit of square measure, 10 meters on each side (100 square meters), 1819, from French, formed 1795 by decree of the French National Convention, from Latin area "vacant piece of ground" (see area).
plural tesserae, "small, square piece of stone," 1650s, from Latin tessera "a die, cube, square tablet with writing on it" used as a token or ticket, from Ionic Greek tessera, neuter of tesseres (Attic tessares) "the numeral four" (from PIE root *kwetwer- "four").
"flat, square table or slab under the molding of the base of a Roman column; square molding at the base of any architectural part," 1610s, from French plinthe (16c.) and directly from Latin plinthus, from Greek plinthos "brick, squared stone," from PIE *splind- "to split, cleave," from root *(s)plei- "to splice, split" (see flint).
