cycloid

(klo̵id′)

noun

Geom. a curve traced by any point on a radius, or an extension of the radius, of a circle which rolls without slipping through one complete revolution along a straight line in a single plane; trochoid

Origin: Gr kykloeidēs, circular < kyklos (see wheel) + -eidēs, -oid

adjective

  1. circular
  2. designating or having fish scales that are roundish in form with smooth edges
  3. designating or of a cyclothymic person

Related Forms:

See cycloid in American Heritage Dictionary 4

cy·cloid

adjective
  1. Resembling a circle.
  2. Zoology
    a. Thin, rounded, and smooth-edged; disklike. Used of fish scales.
    b. Having or composed of such scales.
  3. Psychiatry Afflicted with or relating to cyclothymia.
noun
  1. Mathematics The curve traced by a point on the circumference of a circle that rolls on a straight line.
  2. Zoology A fish having cycloid scales.

Origin: French cycloïde, from Greek kukloeidēs, circular : kuklos, circle; see kwel-1 in Indo-European roots + -oeidēs, -oid.

Related Forms:

  • cycloidal cy·cloiˈdal (-kloidˌl) adjective

(click for a larger image)

cycloid

top: surface view of cycloid scales of a bony fish

bottom: The parametric equation of this cycloid is:

x=r(Θ - sinΘ)

y=r(1 - cosΘ)

Learn more about cycloid

cycloid

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