arch

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A structure, especially one of masonry, forming the curved, pointed, or flat upper edge of an open space and supporting the weight above it, as in a bridge or doorway.
2. n. A structure, such as a freestanding monument, shaped like an inverted U.
3. n. A curve with the ends down and the middle up: the arch of a raised eyebrow.
4. n. Anatomy An organ or structure having a curved or bowlike appearance, especially either of two arched sections of the bony structure of the foot.
5. v. To provide with an arch: arch a passageway.
6. v. To cause to form an arch or similar curve.
7. v. To bend backward: The dancers alternately arched and hunched their backs.
8. v. To span: "the rude bridge that arched the flood” ( Ralph Waldo Emerson).
9. v. To form an arch or archlike curve: The high fly ball arched toward the stands.
10. adj. Chief; principal: their arch foe.
11. adj. Mischievous; roguish: an arch glance.

Century Dictionary and Cyclopedia

1. n. 1. In geometry, any part of the circumference of a circle or other curve; an arc. See arc
2. n. In architecture, a structure built of separate and inelastic blocks, assembled on a curved line in such a way as to retain their position when the structure is supported extraneously only at its two extremities. The separate blocks which compose the arch are called voussoirs or arch-stones. The extreme or lowest voussoirs are termed springers, and the uppermost or central one, when a single stone occupies this position, is called the keystone. The under or concave face of the assembled voussoirs is called the intrados, and the upper or convex face the extrados, of the arch. When the curves of the intrados and extrados are concentric or parallel, the arch is said to be extradosed. The supports which afford resting and resisting points to the arch are piers or pillars, which receive the vertical pressure of the arch, and abutments, which resist its lateral thrust, and which are properly portions of the wall or other structure above the springing and abreast of the shoulder of the arch. The upper part of the pier upon which the arch rests (technically, the point from which it springs) is the impost. The span of an arch is the distance between its opposite imposts. The rise of an arch is the height of the highest point of its intrados above the line of the imposts; this point is sometimes called the under side of the crown, the highest point of the extrados being the crown. The thrust of an arch is the pressure which it exerts outward. This pressure is practically collected, so far as it is manifested as an active force, at a point which cannot be exactly determined theoretically, but is at about one third of the height of the rise of the arch. The thrust must be counteracted by abutments or buttresses. Arches are designated in two ways: First, in a general manner, according to their properties, their uses, their position in a building, or their exclusive employment in a particular style of architecture. Thus, there are arches of equilibration, equipollent arches, arches of discharge, skew and reversed arches, Roman, Pointed, and Saracenic arches. Second, they are named specifically, according to the curve the intrados assumes, when that curve is the section of any of the geometrical solids, as segmental, semicircular, cycloidal, elliptical, parabolical, hyperbolical, or catenarian arches; or from the resemblance of the whole contour of the curve to some familiar object, as lancet arch and horseshoe arch; or from the method used in describing the curve, as equilateral, three-centered, four-centered, ogee, etc. When an arch has one of its imposts higher than the other, it is said to be rampant. Foil arches are arches whose intrados outlines form a series of subordinate arcs called foils, the points of which are termed cusps. A numeral is usually employed to designate the number of foils, as a trefoil arch, a cinquefoil arch, etc.
3. n. Any place covered with an arch or a vault like an arch: as, to pass through the arch of a bridge.
4. n. Any curvature in the form of arch: as, the arch of the aorta; the arch of an eyebrow, of the foot, of the heavens, etc.
5. n. In mining, a portion of a lode left standing, either as being too poor for profitable working or because it is needed to support the adjacent rock.
6. n. The roofing of the fire-chamber of a furnace, as a reverberatory or a glass-furnace; hence, sometimes, the fire-chamber itself.
7. To cover with a vault, or span with an arch.
8. To throw into the shape of an arch or vault; curve: as, the horse arches his neck.
9. To form an arch or arches: as, the sky arches overhead.
10. n. A box or chest; in plural, archives.
11. n. The ark of Noah.
12. n. The ark of the covenant.
13. Chief; principal; preëminent. See arch-.
14. Cunning; sly; shrewd; waggish; mischievous for sport; roguish: now commonly used of facial expression: as, “so arch a leer,”
15. n. A chief; a leader.
16. n. Chief; principal: a prefix much used in composition with words both of native and of foreign origin. See arch.

Wiktionary

1. n. An inverted U shape.
2. n. An arch-shaped arrangement of trapezoidal stones, designed to redistribute downward force outward.
3. n. architecture An architectural element having the shape of an arch
4. n. archaic, geometry An arc; a part of a curve.
5. v. To form into an arch shape
6. adj. ​ Knowing, clever, mischievous.
7. adj. Principal; primary.

GNU Webster's 1913

1. n. (Geom.) Any part of a curved line.
2. n. Usually a curved member made up of separate wedge-shaped solids, with the joints between them disposed in the direction of the radii of the curve; used to support the wall or other weight above an opening. In this sense arches are segmental, round (i. e., semicircular), or pointed.
3. n. A flat arch is a member constructed of stones cut into wedges or other shapes so as to support each other without rising in a curve.
4. n. Any place covered by an arch; an archway.
5. n. Any curvature in the form of arch.
6. v. To cover with an arch or arches.
7. v. To form or bend into the shape of an arch.
8. v. To form into an arch; to curve.
9. adj. Chief; eminent; greatest; principal.
10. adj. Cunning or sly; sportively mischievous; roguish.
11. n. obsolete A chief.

WordNet 3.0

1. v. form an arch or curve
2. adj. naughtily or annoyingly playful
3. n. a curved bony structure supporting or enclosing organs (especially the inner sides of the feet)
4. n. (architecture) a masonry construction (usually curved) for spanning an opening and supporting the weight above it
5. adj. (used of behavior or attitude) characteristic of those who treat others with condescension
6. adj. expert in skulduggery
7. n. a passageway under a curved masonry construction
8. n. a curved shape in the vertical plane that spans an opening