O.E. furh "furrow," from P.Gmc. *furkh- (cf. O.N. for "furrow, drainage ditch;" M.Du. vore, Du. voor; Ger. Furche "furrow"), from PIE *prk- (cf. L. porca "ridge between two furrows," O.Ir. -rech, Welsh rhych "furrow"). "Some scholars connect this word with L. porcus, Eng. FARROW, assigning to the common root the sense 'to root like a swine.' " [OED] The verb meaning "to make wrinkles in one's face, brow, etc." is from 1590s. Related: Furrowed; furrowing.