1550s, of uncertain origin, possibly from Middle French ferler "to furl," from Old French ferliier "chain, tie up, lock away," perhaps from fer "firm" (from Latin firmus; see firm (adj.)) + -lier "to bind" (from Latin ligare). Also said to be a shortening of earlier furdle "to furl or fold." Related: Furled; furling. As a noun from 1640s.