Английский Этимологический словарь - fire (n.)

- O.E. fyr, from P.Gmc. *fuir, from PIE *perjos. Current spelling is attested as early as 1200, but did not fully displace M.E. fier (preserved in fiery) until c.1600. The v. sense of "sack, dismiss" is first recorded 1885 in Amer.Eng., probably from a play on the two meanings of discharge: "to dismiss from a position," and "to fire a gun," the second sense being from "set fire to gunpowder," attested from 1530. The first use of fireman as "person hired to put out (rather than tend) fires" is 1714. Firecracker is Amer.Eng. coinage for what is in England just cracker, but the U.S. word distinguishes it from the word meaning "biscuit." Firefly is attested from 1658. Fired up "angry" is from 1824.