cone

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The surface generated by a straight line, the generator, passing through a fixed point, the vertex, and moving along a fixed curve, the directrix.
• noun A right circular cone.
• noun The figure formed by a cone, bound or regarded as bound by its vertex and a plane section taken anywhere above or below the vertex.
• noun Something having the shape of this figure.
• noun A unisexual reproductive structure of most gymnospermous plants, such as conifers and cycads, typically consisting of a central axis around which there are scaly, overlapping, spirally arranged sporophylls that bear either pollen-containing structures or ovules.
• noun A similar, spore-producing structure of club mosses, horsetails, and spikemosses.
• noun A reproductive structure resembling a cone, such as the female inflorescence of a hop plant or the woody female catkin of an alder.
• noun Physiology One of the photoreceptors in the retina of the eye that is responsible for daylight and color vision. These photoreceptors are most densely concentrated in the fovea centralis, creating the area of greatest visual acuity.
• noun Any of various gastropod mollusks of the family Conidae of tropical and subtropical seas that have a conical, often vividly marked shell and that inject their prey with poisonous toxins, which can be fatal to humans.
• transitive verb To shape (something) like a cone or a segment of one.

from The Century Dictionary.

• To shape so as to resemble the segment of a cone, as the tire or tread of a car-wheel.
• noun The crystalline lens of the compound or faceted eye (ommateum) of an insect.
• noun A pair of equal cones with parallel axes, but with the small base of one in line with the large base of the other, at such a distance that an endless belt on their surfaces or an idle transmitting-wheel between them can transmit power from one to the other. In either form the device may be used to transmit a varying velocity ratio by adjusting belt or wheel so that a large circumference of driver is opposite a small circumference of driver, or the reverse.
• To bear cones: said of coniferous trees.
• noun In geometry: A solid generated by the revolution of a right-angled triangle upon one of its sides as an axis.
• noun A solid the surface of which consists of a circle, which forms its base, and the envelop of all the limited straight lines which join the circumference of the circle to a fixed point lying without the perpendicular to the circle from its center: specifically termed an oblique or scalene cone. See conic.
• noun In modern geom., any surface generated by a line one point in which is fixed.
• noun Anything shaped like a cone.
• noun In anat.: The conarium, or pineal body of the brain.
• noun One of the minute cone-shaped structures forming with the so-called “rods” a layer of the retina. See retina.
• noun In conchology, a shell of the family Conidoe, characterized by its obconic form.
• noun The hill surrounding the crater of a volcano, formed by the gradual accumulation of the ejected material.
• noun A storm-cone.
• noun The vent-plug in the barrel of a firearm.
• noun In spinning, one of the taper drums in the head-stock of a mule, known respectively us the backing-off and drawing-up cones.

from the GNU version of the Collaborative International Dictionary of English.

• transitive verb To render cone-shaped; to bevfl like whe circwlar segoent of a cone.
• noun (Geom.) A solid of the form described by the revolution of a right-angled triangle about one of the sides adjacent to the right angle; -- called also a right cone. More generally, any solid having a vertical point and bounded by a surface which is described by a straight line always passing through that vertical point; a solid having a circle for its base and tapering to a point or vertex.
• noun Anything shaped more or less like a mathematical cone.
• noun (Bot.) The fruit or strobile of the Coniferæ, as of the pine, fir, cedar, and cypress. It is composed of woody scales, each one of which has one or two seeds at its base.
• noun (Zoöl.) A shell of the genus Conus, having a conical form.
• noun (Opt.) the pencil of rays of light which proceed from a radiant point to a given surface, as that of a lens, or conversely.
• noun See in the Vocabulary.
• noun a cone of which the axis is inclined to the plane of its base.
• noun See Cone, 1.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun geometry A surface of revolution formed by rotating a segment of a line around another line that intersects the first line.
• noun geometry A solid of revolution formed by rotating a triangle around one of its altitudes.
• noun topology A space formed by taking the direct product of a given space with a closed interval and identifying all of one end to a point.
• noun A unit of volume, applied solely to marijuana and only while it is in a smokable state; roughly 1.5 cubic centimetres, depending on use.
• noun slang The bowl piece on a bong.
• noun slang The process of smoking cannabis in a bong.
• noun slang A cone-shaped cannabis joint.
• noun slang A passenger on a cruise ship (so-called by employees after traffic cones, from the need to navigate around them)
• noun category theory Given a diagram F : J → C, a cone consists of an object N of C, together with a family of morphisms ψX : N → F(X) indexed by all of the objects of J, such that for every morphism f : X → Y in J, . Then N is the vertex of the cone, whose sides are all the ψX indexed by Ob(J) and whose base is F. The cone is said to be "from N to F" and can be denoted as (N, ψ).
• verb pottery To fashion into the shape of a cone.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a shape whose base is a circle and whose sides taper up to a point