main line

Shaft Shaft, n. [OE. shaft, schaft, AS. sceaft; akin to D. schacht, OHG. scaft, G. schaft, Dan. & Sw. skaft handle, haft, Icel. skapt, and probably to L. scapus, Gr. ????, ????, a staff. Probably originally, a shaven or smoothed rod. Cf. {Scape}, {Scepter}, {Shave}.] 1. The slender, smooth stem of an arrow; hence, an arrow. [1913 Webster]

His sleep, his meat, his drink, is him bereft, That lean he wax, and dry as is a shaft. --Chaucer. [1913 Webster]

A shaft hath three principal parts, the stele [stale], the feathers, and the head. --Ascham. [1913 Webster]

2. The long handle of a spear or similar weapon; hence, the weapon itself; (Fig.) anything regarded as a shaft to be thrown or darted; as, shafts of light. [1913 Webster]

And the thunder, Winged with red lightning and impetuous rage, Perhaps hath spent his shafts. --Milton. [1913 Webster]

Some kinds of literary pursuits . . . have been attacked with all the shafts of ridicule. --V. Knox. [1913 Webster]

3. That which resembles in some degree the stem or handle of an arrow or a spear; a long, slender part, especially when cylindrical. Specifically: (a) (Bot.) The trunk, stem, or stalk of a plant. (b) (Zo["o]l.) The stem or midrib of a feather. See Illust. of {Feather}. (c) The pole, or tongue, of a vehicle; also, a thill. (d) The part of a candlestick which supports its branches. [1913 Webster]

Thou shalt make a candlestick of pure gold . . . his shaft, and his branches, his bowls, his knops, and his flowers, shall be of the same. --Ex. xxv. 31. [1913 Webster] (e) The handle or helve of certain tools, instruments, etc., as a hammer, a whip, etc. (f) A pole, especially a Maypole. [Obs.] --Stow. (g) (Arch.) The body of a column; the cylindrical pillar between the capital and base (see Illust. of {Column}). Also, the part of a chimney above the roof. Also, the spire of a steeple. [Obs. or R.] --Gwilt. (h) A column, an obelisk, or other spire-shaped or columnar monument. [1913 Webster]

Bid time and nature gently spare The shaft we raise to thee. --Emerson. [1913 Webster] (i) (Weaving) A rod at the end of a heddle. (j) (Mach.) A solid or hollow cylinder or bar, having one or more journals on which it rests and revolves, and intended to carry one or more wheels or other revolving parts and to transmit power or motion; as, the shaft of a steam engine. See Illust. of {Countershaft}. [1913 Webster]

4. (Zo["o]l.) A humming bird ({Thaumastura cora}) having two of the tail feathers next to the middle ones very long in the male; -- called also {cora humming bird}. [1913 Webster]

5. [Cf. G. schacht.] (Mining) A well-like excavation in the earth, perpendicular or nearly so, made for reaching and raising ore, for raising water, etc. [1913 Webster]

6. A long passage for the admission or outlet of air; an air shaft. [1913 Webster]

7. The chamber of a blast furnace. [1913 Webster]

{Line shaft} (Mach.), a main shaft of considerable length, in a shop or factory, usually bearing a number of pulleys by which machines are driven, commonly by means of countershafts; -- called also {line}, or {main line}.

{Shaft alley} (Naut.), a passage extending from the engine room to the stern, and containing the propeller shaft.

{Shaft furnace} (Metal.), a furnace, in the form of a chimney, which is charged at the top and tapped at the bottom. [1913 Webster]