Definition of conchoid in English:


Line breaks: con|choid
Pronunciation: /ˈkɒŋkɔɪd


A plane quartic curve consisting of two separate branches either side of and asymptotic to a central straight line (the asymptote), such that if a line is drawn from a fixed point (the pole) to intersect both branches, the part of the line falling between the two branches is of constant length and is exactly bisected by the asymptote.
More example sentences
  • Nicomedes is famous for his treatise On conchoid lines which contain his discovery of the curve known as the conchoid of Nicomedes.
  • The ruler has a fixed distance marked on it and one mark is kept on a given line while the other traces the conchoid curve.
  • Nicomedes, who was highly critical of Eratosthenes' mechanical solution, gave a construction which used the conchoid curve which he also used to solve the problem of trisection of an angle.


early 18th century: from conch + -oid.

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