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cycloid
(sī′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
- circular
- designating or having fish scales that are roundish in form with smooth edges
- designating or of a cyclothymic person
Related Forms:
- cycloidal adjective
See cycloid in American Heritage Dictionary 4
cy·cloid
adjective- Resembling a circle.
- Zoology a. Thin, rounded, and smooth-edged; disklike. Used of fish scales.b. Having or composed of such scales.
- Psychiatry Afflicted with or relating to cyclothymia.
- Mathematics The curve traced by a point on the circumference of a circle that rolls on a straight line.
- 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)
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