Back.
The part of an object against which the back of a person leans, as of a chair, carriage, etc. The rear portion of an object. The upper part of a thing, as of an arch, handrail, saw, etc.1. (Forging.) A cast-iron plate forming the backwall of a forge, and through which the blast enters by a tuyere. When the back consists of an iron cistern, it is called a water-back. When it consists of a chamber in which the airblast is heated, it is a heating-back.
2. (Bookbinding.) The part to which the sides of the cover are attached, and which receives the lettering.
3. (Architecture.) a. The rear surface of a wall. b. The rear wall of a fireplace. c. The extrados of an arch or vault. d. The rear part of a stone or ashlar, parallel with the face or exposed surface.
4. (Cork-cutting.) The burnt side of a slab of cork.
5. (Brewing. etc.) A vat or cistern. a. Water-back: a supply cistern in a brewery, etc., containing water for mashing. b. Under-back: a cistern below the mash-tun, which receives the wort therefrom. c. Hop-back: a cistern below the copper, which receives the infusion of malt and hops from the latter. d. Jack-back: the same as hop-back. e. (Glue-making.) Settling-back: a cistern in which a solution of glue from the kettle is received and kept warm till the impurities have time to settle. f. (Distilling.) Wash-back: a cistern or vat in which the wort is fermented to form wash for distillation. g. Spirit-back: the cistern which receives the spirit. In this sense the word is nearly allied to beck; as a dye-beck or soap-beck in a dye-house. See Beck.
6. (Carpentry.) a. The upper surface of a handrail; the under side is the breast. b. The same distinctions apply to the ribs of domes and rafters of roofs. c. The back of a window is the wainscoting below the sash-frame and extending to the floor. d. The upper edge of a saw as opposed to the edge which is serrated.
7. (Mining.) a. The part of a lode nearest to the surface. b. The ground between one level and another is the back of a level.
8. (Shipbuilding.) a. The convex surface of a compass-timber. b. Figuratively, the keel and keelson of a ship. c. A timber bolted on behind the sternpost.
9. (Nautical.) a. To back an anchor: to place a small auxiliary anchor ahead of the one from which the ship rides. b. To back a sail: to brace a yard so that the wind blows in front of it. c. To back astern: to give the vessel sternway. d. To back a rope: to put on a preventer to take a part of the strain. e. To back the worming: to fill the crevices between the strands, to bring the surface flush and even, ready for serving.
