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cone

cone


cone  (kn)
n.
1. Mathematics
a. The surface generated by a straight line, the generator, passing through a fixed point, the vertex, and moving along a fixed curve, the directrix.
b. A right circular cone.
2.
a. 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.
b. Something having the shape of this figure: the cone of illuminated drops spilling beneath a street lamp (Anne Tyler).
3. Botany
a. A unisexual reproductive structure of gymnospermous plants such as conifers and cycads, typically consisting of a central axis around which there are scaly, overlapping, spirally arranged sporophylls that develop pollen-bearing sacs or naked ovules or seeds.
b. A similar structure that produces spores on club mosses, horsetails, and spike mosses.
c. Any reproductive structure resembling a cone, such as a cluster of hop or alder fruits.
4. 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.
5. Any of various gastropod mollusks of the family Conidae of tropical and subtropical seas, having a conical, often vividly marked shell and the ability to inflict a poisonous, sometimes fatal sting.
tr.v. coned, con·ing, cones
To shape (something) like a cone or a segment of one.

[French c?ne and Middle English cone, angle of a quadrant, both from Latin cnus, from Greek knos; see k- in Indo-European roots.]
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cone
top: right circular cone
bottom: cones and rods of a human eye

cone [kəʊn]
n
1. (Mathematics)
a.  a geometric solid consisting of a plane base bounded by a closed curve, often a circle or an ellipse, every point of which is joined to a fixed point, the vertex, lying outside the plane of the base. A right circular cone has a vertex perpendicularly above or below the centre of a circular base. Volume of a cone: ⅓πr2h, where r is the radius of the base and h is the height of the cone
b.  a geometric surface formed by a line rotating about the vertex and connecting the peripheries of two closed plane bases, usually circular or elliptical, above and below the vertex See also conic section
2. anything that tapers from a circular section to a point, such as a wafer shell used to contain ice cream
3. (Life Sciences & Allied Applications / Botany)
a.  the reproductive body of conifers and related plants, made up of overlapping scales, esp the mature female cone, whose scales each bear a seed
b.  a similar structure in horsetails, club mosses, etc. Technical name strobilus
4. (Engineering / Civil Engineering) a small cone-shaped bollard used as a temporary traffic marker on roads
5. (Life Sciences & Allied Applications / Anatomy) Also called retinal cone any one of the cone-shaped cells in the retina of the eye, sensitive to colour and bright light
vb
(tr) to shape like a cone or part of a cone
[from Latin cōnus, from Greek kōnus pine cone, geometrical cone]

cone  (kn)
1. A three-dimensional surface or solid object in which the base is a circle and upper surface narrows to form a point. The surface of a cone is formed mathematically by moving a line that passes through a fixed point (the vertex) along a circle.
2. A rounded or elongated reproductive structure that consists of sporophylls or scales arranged spirally or in an overlapping fashion along a central stem, as in conifers and cycads. For example, the familiar woody pinecone is actually the female cone, made up of ovule-bearing scales. The smaller male cones of the pine consist of thin overlapping microsporophylls. These produce pollen that is carried by the wind to fertilize ovules in the female cones. When the seeds in the female cones mature, the cones of many pine species expand to release them. In some pine species, cones release seeds only in response to the presence of fire. See also strobilus.
3. One of the cone-shaped cells in the retina of the eye of many vertebrate animals. Cones are extremely sensitive to light and can distinguish among different wavelengths. Cones are responsible for vision during daylight and for the ability to see colors. Compare rod.
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cone
The equation for determining the volume (V) of a cone is V = 1/3 r2h.


cone  /kon/  n. an object pointed at one end and then becoming wider at the other end: An ice-cream cone is wide at the top but may be pointed at the bottom. cone

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