c. 1600, "one who or that which transforms," agent noun from transform (v.). Meaning "device to reduce electrical currents" is from 1882.
1813, designating electricity produced by chemical action, formed in recognition of Italian physicist Alessandro Volta (1745-1827), who perfected a chemical process used in electrical batteries, + -ic.
before vowels electr-, word-forming element meaning "electrical, electricity," Latinized form of Greek ēlektro-, combining form of ēlektron "amber" (see electric). As a stand-alone, formerly often short for electrotype, electroplate.
"scanning field," 1934 in electrical engineering, from German Raster "screen, frame," from Latin rastrum "rake," from rasum, from rodere "to scrape" (see rodent). Related: Rasterization; rasterize. From Latin form rastellum comes French râteau "rake," formerly ratel, originally rastel.