What is "discharging arch"

Discharge \Dis*charge"\, v. t. [imp. & p. p. Discharged; p. pr. & vb. n. Discharging.] [OE. deschargen, dischargen, OF. deschargier, F. d['e]charger; pref. des- (L. dis) + chargier, F. charger. See Charge.]

1. To relieve of a charge, load, or burden; to empty of a load or cargo; to unburden; to unload; as, to discharge a vessel.

2. To free of the missile with which anything is charged or loaded; to let go the charge of; as, to discharge a bow, catapult, etc.; especially, said of firearms, -- to fire off; to shoot off; also, to relieve from a state of tension, as a Leyden jar.

   The galleys also did oftentimes, out of their prows, discharge their great pieces against the city.
   --Knolles.

   Feeling in other cases discharges itself in indirect muscular actions.
   --H. Spencer.

3. To of something weighing upon or impeding over one, as a debt, claim, obligation, responsibility, accusation, etc.; to absolve; to acquit; to clear.

   Discharged of business, void of strife.
   --Dryden.

   In one man's fault discharge another man of his duty.
   --L'Estrange.

4. To relieve of an office or employment; to send away from service; to dismiss.

   Discharge the common sort With pay and thanks.
   --Shak.

   Grindal . . . was discharged the government of his see.
   --Milton.

5. To release legally from confinement; to set at liberty; as, to discharge a prisoner.

6. To put forth, or remove, as a charge or burden; to take out, as that with which anything is loaded or filled; as, to discharge a cargo.

7. To let fly, as a missile; to shoot.

   They do discharge their shot of courtesy.
   --Shak.

8. To set aside; to annul; to dismiss.

   We say such an order was ``discharged on appeal.''
   --Mozley & W.

   The order for Daly's attendance was discharged.
   --Macaulay.

9. To throw off the obligation of, as a duty or debt; to relieve one's self of, by fulfilling conditions, performing duty, trust, and the like; hence, to perform or execute, as an office, or part.

   Had I a hundred tongues, a wit so large As could their hundred offices discharge.
   --Dryden.

10. To send away (a creditor) satisfied by payment; to pay one's debt or obligation to. [Obs.]

    If he had The present money to discharge the Jew.
    --Shak.

11. To give forth; to emit or send out; as, a pipe discharges water; to let fly; to give expression to; to utter; as, to discharge a horrible oath.

12. To prohibit; to forbid. [Scot. Obs.]
    --Sir W. Scott.

13. (Textile Dyeing & Printing) To bleach out or to remove or efface, as by a chemical process; as, to discharge the color from a dyed fabric in order to form light figures on a dark ground.

    Discharging arch (Arch.), an arch over a door, window, or other opening, to distribute the pressure of the wall above. See Illust. of Lintel.

    Discharging piece, Discharging strut (Arch.), a piece set to carry thrust or weight to a solid point of support.

    Discharging rod (Elec.), a bent wire, with knobs at both ends, and insulated by a glass handle. It is employed for discharging a Leyden jar or an electrical battery. See Discharger.

    Syn: See Deliver.

A discharging arch or relieving arch is an arch built over a lintel or architrave to take off the superincumbent weight.