Screw n.
 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.
 Note: ☞ 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.
 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]
 7. A small packet of tobacco. [Slang]
 8. An unsound or worn-out horse, useful as a hack, and commonly of good appearance.
 9. Math. A straight line in space with which a definite linear magnitude termed the pitch is associated (cf. 5th Pitch, 10 (b)). It is used to express the displacement of a rigid body, which may always be made to consist of a rotation about an axis combined with a translation parallel to that axis.
 10. Zool. An amphipod crustacean; as, the skeleton screw (Caprella). See Sand screw, under Sand.
 Archimedes screw, Compound screw, Foot screw, etc. See under Archimedes, Compound, Foot, etc.
 A screw loose, something out of order, so that work is not done smoothly; as, there is a screw loose somewhere. --H. Martineau.
 Endless screw, or perpetual screw, a screw used to give motion to a toothed wheel by the action of its threads between the teeth of the wheel; -- called also a worm.
 Lag screw. See under Lag.
 Micrometer screw, a screw with fine threads, used for the measurement of very small spaces.
 Right and left screw, a screw having threads upon the opposite ends which wind in opposite directions.
 Screw alley. See Shaft alley, under Shaft.
 Screw bean. Bot. (a) The curious spirally coiled pod of a leguminous tree (Prosopis pubescens) growing from Texas to California. It is used for fodder, and ground into meal by the Indians. (b) The tree itself. Its heavy hard wood is used for fuel, for fencing, and for railroad ties.
 Screw bolt, a bolt having a screw thread on its shank, in distinction from a key bolt. See 1st Bolt, 3.
 Screw box, a device, resembling a die, for cutting the thread on a wooden screw.
 Screw dock. See under Dock.
 Screw engine, a marine engine for driving a screw propeller.
 Screw gear. See Spiral gear, under Spiral.
 Screw jack. Same as Jackscrew.
 Screw key, a wrench for turning a screw or nut; a spanner wrench.
 Screw machine. (a) One of a series of machines employed in the manufacture of wood screws. (b) A machine tool resembling a lathe, having a number of cutting tools that can be caused to act on the work successively, for making screws and other turned pieces from metal rods.
 Screw pine Bot., any plant of the endogenous genus Pandanus, of which there are about fifty species, natives of tropical lands from Africa to Polynesia; -- named from the spiral arrangement of the pineapple-like leaves.
 Screw plate, a device for cutting threads on small screws, consisting of a thin steel plate having a series of perforations with internal screws forming dies.
 Screw press, a press in which pressure is exerted by means of a screw.
 Screw propeller, a screw or spiral bladed wheel, used in the propulsion of steam vessels; also, a steam vessel propelled by a screw.
 Screw shell Zool., a long, slender, spiral gastropod shell, especially of the genus Turritella and allied genera. See Turritella.
 Screw steamer, a steamship propelled by a screw.
 Screw thread, the spiral rib which forms a screw.
 Screw stone Paleon., the fossil stem of an encrinite.
 Screw tree Bot., any plant of the genus Helicteres, consisting of about thirty species of tropical shrubs, with simple leaves and spirally twisted, five-celled capsules; -- also called twisted-horn, and twisty.
 Screw valve, a stop valve which is opened or closed by a screw.
 Screw worm Zool., the larva of an American fly (Compsomyia macellaria), allied to the blowflies, which sometimes deposits its eggs in the nostrils, or about wounds, in man and other animals, with fatal results.
 Screw wrench. (a) A wrench for turning a screw. (b) A wrench with an adjustable jaw that is moved by a screw.
 To put the screws on or To put the screw on, to use pressure upon, as for the purpose of extortion; to coerce.
 To put under the screw or To put under the screws, to subject to pressure; to force.
 Wood screw, a metal screw with a sharp thread of coarse pitch, adapted to holding fast in wood. See Illust. of Wood screw, under Wood.


 Foot n.; pl. Feet
 1. Anat. The terminal part of the leg of man or an animal; esp., the part below the ankle or wrist; that part of an animal upon which it rests when standing, or moves. See Manus, and Pes.
 2. Zool. The muscular locomotive organ of a mollusk. It is a median organ arising from the ventral region of body, often in the form of a flat disk, as in snails. See Illust. of Buccinum.
 3. That which corresponds to the foot of a man or animal; as, the foot of a table; the foot of a stocking.
 4. The lowest part or base; the ground part; the bottom, as of a mountain, column, or page; also, the last of a row or series; the end or extremity, esp. if associated with inferiority; as, the foot of a hill; the foot of the procession; the foot of a class; the foot of the bed; ; the foot of the page.
 And now at foot
 Of heaven's ascent they lift their feet.   --Milton.
 5. Fundamental principle; basis; plan; -- used only in the singular.
    Answer directly upon the foot of dry reason.   --Berkeley.
 6. Recognized condition; rank; footing; -- used only in the singular. [R.]
    As to his being on the foot of a servant.   --Walpole.
 7. A measure of length equivalent to twelve inches; one third of a yard. See Yard.
 Note: ☞ This measure is supposed to be taken from the length of a man's foot. It differs in length in different countries. In the United States and in England it is 304.8 millimeters.
 8. Mil. Soldiers who march and fight on foot; the infantry, usually designated as the foot, in distinction from the cavalry. “Both horse and foot.”
 9. Pros. A combination of syllables consisting a metrical element of a verse, the syllables being formerly distinguished by their quantity or length, but in modern poetry by the accent.
 10. Naut. The lower edge of a sail.
 Note: ☞ Foot is often used adjectively, signifying of or pertaining to a foot or the feet, or to the base or lower part. It is also much used as the first of compounds.
  Foot artillery. Mil. (a) Artillery soldiers serving in foot. (b) Heavy artillery. --Farrow.
 Foot bank Fort., a raised way within a parapet.
 Foot barracks Mil., barracks for infantery.
 Foot bellows, a bellows worked by a treadle. --Knight.
 Foot company Mil., a company of infantry. --Milton.
 Foot gear, covering for the feet, as stocking, shoes, or boots.
 Foot hammer Mach., a small tilt hammer moved by a treadle.
 Foot iron. (a) The step of a carriage. (b) A fetter.
 Foot jaw. Zool. See Maxilliped.
 Foot key Mus., an organ pedal.
 Foot level Gunnery, a form of level used in giving any proposed angle of elevation to a piece of ordnance. --Farrow.
 Foot mantle, a long garment to protect the dress in riding; a riding skirt. [Obs.]
 Foot page, an errand boy; an attendant. [Obs.]
 Foot passenger, one who passes on foot, as over a road or bridge.
 Foot pavement, a paved way for foot passengers; a footway; a trottoir.
 Foot poet, an inferior poet; a poetaster. [R.] --Dryden.
 Foot post. (a) A letter carrier who travels on foot. (b) A mail delivery by means of such carriers.
 Fot pound, ∧ Foot poundal. Mech. See Foot pound and Foot poundal, in the Vocabulary.
 Foot press Mach., a cutting, embossing, or printing press, moved by a treadle.
 Foot race, a race run by persons on foot. --Cowper.
 Foot rail, a railroad rail, with a wide flat flange on the lower side.
 Foot rot, an ulcer in the feet of sheep; claw sickness.
 Foot rule, a rule or measure twelve inches long.
 Foot screw, an adjusting screw which forms a foot, and serves to give a machine or table a level standing on an uneven place.
 Foot secretion. Zool. See Sclerobase.
 Foot soldier, a soldier who serves on foot.
 Foot stick Printing, a beveled piece of furniture placed against the foot of the page, to hold the type in place.
 Foot stove, a small box, with an iron pan, to hold hot coals for warming the feet.
 Foot tubercle. Zool. See Parapodium.
 Foot valve Steam Engine, the valve that opens to the air pump from the condenser.
 Foot vise, a kind of vise the jaws of which are operated by a treadle.
 Foot waling Naut., the inside planks or lining of a vessel over the floor timbers. --Totten.
 Foot wall Mining, the under wall of an inclosed vein.
  By foot, or On foot, by walking; as, to pass a stream on foot.
 Cubic foot. See under Cubic.
 Foot and mouth disease, a contagious disease (Eczema epizoötica) of cattle, sheep, swine, etc., characterized by the formation of vesicles and ulcers in the mouth and about the hoofs.
 Foot of the fine Law, the concluding portion of an acknowledgment in court by which, formerly, the title of land was conveyed. See Fine of land, under Fine, n.; also Chirograph. (b).
 Square foot. See under Square.
 To be on foot, to be in motion, action, or process of execution.
 To keep the foot Script., to preserve decorum. “Keep thy foot when thou goest to the house of God.” --Eccl. v. 1.
 To put one's foot down, to take a resolute stand; to be determined. [Colloq.]
 To put the best foot foremost, to make a good appearance; to do one's best. [Colloq.]
 To set on foot, to put in motion; to originate; as, to set on foot a subscription.
 To put one on his feet, or set one on his feet, to put one in a position to go on; to assist to start.
 Under foot. (a) Under the feet; (Fig.) at one's mercy; as, to trample under foot. --Gibbon. (b) Below par. [Obs.] “They would be forced to sell . . . far under foot.” --Bacon.