Definition of "half-staff"

[T]he agents of the steamship lines drowned their sorrow in rum and ran the house flags to half-staff.

c. 1900, Richard Harding Davis, Billy and the Big Stick

Marshal Joseph Pilsudski, Poland's man of power, died here tonight. . Flags were lowered to half staffs.

1935 May 13, “Ninth Anniversary of Coup”, in New York Times, page 6

President Bush's decision to honor Pope John Paul II by ordering flags lowered to half-staff on all public buildings has reignited a debate about the separation of church and state.

2005 April 6, Felisa Cardona, "Flag order spurs controversy," Denver Post (USA), p. B-01, (retrieved 29 Aug. 2011)

[T]he flags at Ottawa fire stations were lowered to half-staff in tribute.

2008 August 5, “Two men electrocuted fixing flat on firetruck”, in Ottawa Citizen, Canada, retrieved 29 Aug. 2011