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Having equal angles; as, an equiangular figure; a square is equiangular. Equiangular spiral. (Math.) See under Spiral, n. -- Mutually equiangular, applied to two figures, when every angle of the one has its equal among the angles of the other.

That portion of the interior of a spiral shell which can be seen by looking into the aperture.

formed by the infolding of the whole wall of the cerebrum. -- Fissure needle (Surg.), a spiral needle for catching together the gaping lips of wounds. Knight. -- Fissure of rolando (Anat.), the furrow separating the frontal from the parietal lobe in the cerebrum. -- Fissure of Sylvius (Anat.), a deep cerebral fissu…

ed also Italian iron, or gaufering iron. Knight. -- Fluting lathe, a machine for forming spiral flutes, as on balusters, table legs, etc.

of the mainspring by having the chain from the barrel which contains the spring wind in a spiral groove on the surface of the cone in such a manner that the diameter of the cone at the point where the chain acts may correspond with the degree of tension of the spring.

One of the subclasses of fishes. They have an arterial cone and bulb, spiral intestinal valve, and the optic nerves united by a chiasma. Many of the species are covered with bony plates, or with ganoid scales; others have cycloid scales.

One of the classes of Mollusca, of great extent. It includes most of the marine spiral shells, and the land and fresh-water snails. They generally creep by means of a flat, muscular disk, or foot, on the ventral side of the body. The head usually bears one or two pairs of tentacles. See Mollusca. [Written also Gasterop…

To revolve round a central point; to move spirally about an axis, as a tornado; to revolve.

The act of turning or whirling, as around a fixed center; a circular or spiral motion; motion about an axis; rotation; revolution. The gyrations of an ascending balloon. De Quincey. If a burning coal be nimbly moved round in a circle, with gyrations continually repeated, the whole circle will appear like fire. Sir I. N…

Moving in a circle, or spirally; revolving; whirling around.

Spiral in arrangement or action.

Of or pertaining to, or in the form of, a helix; spiral; as, a helical staircase; a helical spring. -- Hel"i*cal*ly, adv.

Having the form of a helix; spiral.

Curled; spiral; helicoid; -- applied esp. to certain arteries of the penis.

An instrument for drawing spiral lines on a plane.

Spiral; curved, like the spire of a univalve shell.

Spiral. Helispherical line (Math.). the rhomb line in navigation. [R.]

lix is the curve formed by the thread of the ordinary screw. It is distinguished from the spiral, all the convolutions of which are in the plane.

Having spirals of changing direction. Gray.

Running in the same direction; -- said of stems twining round a support, or of the spiral succession of leaves on stems and their branches.