Definitions

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. Any of a family of curves defined as the locus of a point, P, on a line from a given fixed point to a given curve, C, where the distance along the line from C to P remains constant.

from the GNU version of the Collaborative International Dictionary of English

  • n. A curve, of the fourth degree, first made use of by the Greek geometer, Nicomedes, who invented it for the purpose of trisecting an angle and duplicating the cube.

from The Century Dictionary and Cyclopedia

  • n. A plane curve invented by one Nicomedes, probably in the second century before Christ, and defined by him as such that if a straight line be drawn from a certain fixed point, called the pole of the curve, to the curve, the part of the line intercepted between the curve and a fixed line (now called its asymptote) is always equal to a fixed distance.
  • n. It is a curve of the fourth order and of the sixth class, unless it has a cusp at P, when it is of the fifth class. It has a double point at the pole, and meets its asymptote at four consecutive points at infinity. It has two branches.
  • Same as conchoidal.

Etymologies

From Latin concha ("mussel") (from Ancient Greek κόνχη (konchē)) +‎ -oid. Due to the curved patterns on a mussel shell. (Wiktionary)

Examples

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  • A curve, of the fourth degree, first made use of by the Greek geometer, Nicomedes, who invented it for the purpose of trisecting an angle and duplicating the cube.

    August 29, 2008