Foil comes from Middle English foilen ('to trample, defeat'), from Old French fouler ('to trample, full cloth'), from Vulgar Latin *fullare, from Latin fullo ('fuller of cloth'). The 'thin metal sheet' sense is from Old French foil ('leaf'), from Latin folium. The development is chiefly a borrowing or learned continuation, carrying an older form and meaning into English rather than building the word from a purely native base. In present use, it is used as a noun and verb meaning "a person or thing that contrasts with and enhances another; to thwart", so the historical material remains connected with the current sense rather than standing as bare ancestry. The wider English family includes derivatives such as foiled and foiling, showing how the same historical material continues to organize neighboring vocabulary. The named historical forms include Old French fouler and Latin fullo, keeping the history tied to concrete forms rather than a loose resemblance.