flour (n.)
early 13c., flur "flower" (see flower (n.)); meaning "finer portion of ground grain" is mid-13c., from the notion of flour as the "finest part" of meal (compare French fleur de farine), as distinguished from the coarser parts (meal). Spelled flower until flour became the accepted form c.1830 to end confusion.
flour (v.)
"to sprinkle with flour," 1650s, from flour (n.). Related: Floured; flouring.