plate (n.)youdaoicibaDictYouDict[plate 词源字典]
mid-13c., "flat sheet of gold or silver," also "flat, round coin," from Old French plate "thin piece of metal" (late 12c.), from Medieval Latin plata "plate, piece of metal," perhaps via Vulgar Latin *plattus, formed on model of Greek platys "flat, broad" (see plaice (n.)). The cognate in Spanish (plata) and Portuguese (prata) has become the usual word for "silver," superseding argento via shortening of *plata d'argento "plate of silver, coin." Meaning "table utensils" (originally of silver or gold only) is from Middle English. Meaning "shallow dish for food," now usually of china or earthenware, originally of metal or wood, is from mid-15c. Baseball sense is from 1857. Geological sense is first attested 1904; plate tectonics first recorded 1969. Plate-glass first recorded 1727.[plate etymology, plate origin, 英语词源]
shield (n.)youdaoicibaDictYouDict
Old English scield, scild "shield; protector, defense," literally "board," from Proto-Germanic *skelduz (cognates: Old Norse skjöldr, Old Saxon skild, Middle Dutch scilt, Dutch schild, German Schild, Gothic skildus), from *skel- "divide, split, separate," from PIE root *(s)kel- (1) "to cut" (see scale (n.1)). Perhaps the notion is of a flat piece of wood made by splitting a log. Shield volcano (1911) translates German Schildvulkan (1910). Plate tectonics sense is from 1906, translating Suess (1888).