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; from PIE root *dher- "to hold firmly, support") + -lier "to bind" (from Latin ligare; from PIE root *leig- "to tie, bind"). Also said to be a shortening of earlier furdle "to furl or fold." Related: Furled; furling. As a noun from 1640s.