cissoid

American  

[sis-oid] / ˈsɪs ɔɪd /

noun

Geometry.

1. a curve having a cusp at the origin and a point of inflection at infinity. Equation: r = 2 a sin(θ)tan(θ).

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cissoid British  

/ ˈsɪsɔɪd /

noun

1. a geometric curve whose two branches meet in a cusp at the origin and are asymptotic to a line parallel to the y -axis. Its equation is y ²(2a – x ) =x ³ where 2a is the distance between the y -axis and this line

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adjective

1. contained between the concave sides of two intersecting curves Compare sistroid

Other Word Forms

• cissoidal adjective

Etymology

Origin of cissoid

1650–60; < Greek kissoeidḗs, equivalent to kiss ( ós ) ivy + -oeidēs -oid

Example Sentences

The term cissoid has been given in modern times to curves generated in similar manner from other figures than the circle, and the form described above is distinguished as the cissoid of Diocles.

From Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 4 "Cincinnatus" to "Cleruchy" by Various

A cissoid angle is the angle included between the concave sides of two intersecting curves; the convex sides include the sistroid angle.

From Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 4 "Cincinnatus" to "Cleruchy" by Various