cycloid

American  

[sahy-kloid] / ˈsaɪ klɔɪd /

adjective

1. resembling a circle; circular.

2. (of the scale of a fish) smooth-edged, more or less circular in form, and having concentric striations.

3. (of a fish) having such scales.

4. Psychiatry. of or noting a personality type characterized by wide fluctuation in mood within the normal range.

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noun

1. a cycloid fish.

2. Geometry. a curve generated by a point on the circumference of a circle that rolls, without slipping, on a straight line.

cycloid British  

/ ˈsaɪklɔɪd /

adjective

1. resembling a circle

2. (of fish scales) rounded, thin, and smooth-edged, as those of the salmon

3. psychiatry (of a type of personality) characterized by exaggerated swings of mood between elation and depression See also cyclothymia

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noun

1. geometry the curve described by a point on the circumference of a circle as the circle rolls along a straight line Compare trochoid

2. a fish that has cycloid scales

cycloid Scientific  

/ sī′kloid′ /

1. Resembling a circle.

2. Thin, rounded, and smooth-edged, like a disk. Used of fish scales.

3. The curve traced by a point on the circumference of a circle that rolls on a straight line.

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Other Word Forms

• cycloidal adjective
• cycloidally adverb

Etymology

Origin of cycloid

First recorded in 1655–65, cycloid is from the Greek word kykloeidḗs like a circle. See cycl-, -oid

Example Sentences

Kahn played with natural light in the Fort Worth building, suffused with skylights, reflectors and cycloid barrel vaults.

From New York Times

That curve, called a cycloid, is produced by a point on the circumference of a circle or wheel as it rolls along a straight line.

From New York Times

There are connections to be made between some of these displays — even the “Tracks of Galileo” with its allusion to “cycloids” and the rectangular-wheeled trike — that might have also been subtly explored.

From New York Times

This curve of quickest descent, as it is sometimes called, is, in a vacuum, the same as the cycloid.

From Project Gutenberg

It is physically impossible to mill out a concave cycloid, by any means whatever, because at the pitch line its radius of curvature is zero, and a milling cutter must have a sensible diameter.

From Project Gutenberg