-raf, -rȧf noun
Etymology: French oscillographe, from oscillo- (from Latin oscillare ) + -graphe -graph
: an instrument that produces in the form of a continuous curve a permanent record (as a graph or a photograph) of periodic or irregular variations in an electrical quantity (as voltage) and often indirectly in some related quantity (as sound pressure) by means of a moving element (as a galvanometer needle or a vibrating beam of cathode rays) — compare oscilloscope
• os·cil·lo·graph·ic ̷ ̷| ̷ ̷ ̷ ̷|grafik adjective
• os·cil·lo·graph·i·cal·ly -fə̇k(ə)lē adverb
• os·cil·log·ra·phy ˌäsəˈlägrəfē noun -es