The old carl gae them a screed of doctrine; ye might have heard him
a mile down the wind.
Sir W. Scott.
Screen (skrn), n. [OE. scren, OF. escrein, escran, F. écran, of
uncertain origin; cf. G. schirm a screen, OHG. scirm, scerm a
protection, shield, or G. schragen a trestle, a stack of wood, or G.
schranne a railing.] 1. Anything that separates or cuts off
inconvenience, injury, or danger; that which shelters or conceals from
view; a shield or protection; as, a fire screen.
Your leavy screens throw down.
Shak.
Some ambitious men seem as screens to princes in matters of danger
and envy.
Bacon.
2. (Arch.) A dwarf wall or partition carried up to a certain height for
separation and protection, as in a church, to separate the aisle from
the choir, or the like.
3. A surface, as that afforded by a curtain, sheet, wall, etc., upon
which an image, as a picture, is thrown by a magic lantern, solar
microscope, etc.
4. A long, coarse riddle or sieve, sometimes a revolving perforated
cylinder, used to separate the coarser from the finer parts, as of
coal, sand, gravel, and the like.
Screen (skrn), v. t. [imp. & p. p. Screened (?); p. pr. & vb. n.
Screening.] 1. To provide with a shelter or means of concealment; to
separate or cut off from inconvenience, injury, or danger; to shelter;
to protect; to protect by hiding; to conceal; as, fruits screened from
cold winds by a forest or hill.
They were encouraged and screened by some who were in high
commands.
Macaulay.
2. To pass, as coal, gravel, ashes, etc., through a screen in order to
separate the coarse from the fine, or the worthless from the valuable;
to sift.
Screen"ings (?), n. pl. The refuse left after screening sand, coal,
ashes, etc.
Screw (skr), n. [OE. scrue, OF. escroue, escroe, female screw, F.
écrou, L. scrobis a ditch, trench, in LL., the hole made by swine in
rooting; cf. D. schroef a screw, G. schraube, Icel. skrfa.] 1. A
cylinder, or a cylindrical perforation, having a continuous rib, called
the thread, winding round it spirally at a constant inclination, so as
to leave a continuous spiral groove between one turn and the next, --
used chiefly for producing, when revolved, motion or pressure in the
direction of its axis, by the sliding of the threads of the cylinder in
the grooves between the threads of the perforation adapted to it, the
former being distinguished as the external, or male screw, or, more
usually the screw; the latter as the internal, or female screw, or,
more usually, the nut.
The screw, as a mechanical power, is a modification of the inclined
plane, and may be regarded as a right-angled triangle wrapped round a
cylinder, the hypotenuse of the marking the spiral thread of the screw,
its base equaling the circumference of the cylinder, and its height the
pitch of the thread.
2. Specifically, a kind of nail with a spiral thread and a head with a
nick to receive the end of the screw-driver. Screws are much used to
hold together pieces of wood or to fasten something; -- called also
wood screws, and screw nails. See also Screw bolt, below.
3. Anything shaped or acting like a screw; esp., a form of wheel for
propelling steam vessels. It is placed at the stern, and furnished with
blades having helicoidal surfaces to act against the water in the
manner of a screw. See Screw propeller, below.
4. A steam vesel propelled by a screw instead of wheels; a screw
steamer; a propeller.
5. An extortioner; a sharp bargainer; a skinflint; a niggard.
Thackeray.
6. An instructor who examines with great or unnecessary severity; also,
a searching or strict examination of a student by an instructor. [Cant,
American Colleges]