Definitions

from The American Heritage® Dictionary of the English Language, 5th Edition.

  • adjective Resembling a circle.
  • adjective Relating to or being a kind of fish scale that is thin, rounded, and smooth-edged and often shows concentric growth rings.
  • adjective Having cycloid scales.
  • adjective Psychology Afflicted with or relating to cyclothymia.
  • noun The curve traced by a point on the circumference of a circle that rolls on a straight line.

from The Century Dictionary.

  • Resembling a circle; having a circular form.
  • Specifically In ichthyology: More or less circular, with concentric striations: applied to the scales of certain fishes. See cut under scale.
  • Having somewhat circular scales, as a fish; specifically, pertaining to the Cycloidei.
  • noun A curve generated by a point in the circumference or on a radius of a circle when the circle is rolled along a straight line and kept always in the same plane.
  • noun In ichthyology, a cycloid fish; a fish with cycloid scales, or one of the Cycloidei.
  • In chem., containing a cycle or ring of atoms: used especially of the structure of organic compounds.

from the GNU version of the Collaborative International Dictionary of English.

  • noun (Zoöl.) One of the Cycloidei.
  • adjective (Zoöl.) Of or pertaining to the Cycloidei.
  • adjective (Zoöl.) a fish scale which is thin and shows concentric lines of growth, without serrations on the margin.
  • noun (Geom.) A curve generated by a point in the plane of a circle when the circle is rolled along a straight line, keeping always in the same plane.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun geometry The locus of a point on the circumference of a circle that rolls without slipping on a fixed straight line.
  • noun zoology A fish having cycloid scales.
  • adjective Resembling a circle; cycloidal.
  • adjective zoology (of fish scales) Thin and rounded, with smooth edges.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • adjective resembling a circle
  • noun a line generated by a point on a circle rolling along a straight line

Etymologies

from The American Heritage® Dictionary of the English Language, 4th Edition

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

Examples

  • 8.13 A Beautiful Curve ∗ One of the most wonderful curves I can think of, and one that had a great in fl uence on me in my youth, is called a cycloid, which is the locus ∗ ∗ of a fi xed point on the circumference of a circle as it rolls, without slipping, along a straight line (Figure 8.8).

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  • A cycloid is a curve traced by a point in the circumference of a wheel when the wheel is rolled along in a straight line.

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  • Newton solved it correctly; he showed that the curve was a part of what is termed a cycloid -- that is to say, a curve like that which is described by a point on the rim of a carriage-wheel as the wheel runs along the ground.

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  • Thin, translucent, and lacking enamel as well as dentine, these modern structures are known as cycloid and ctenoid scales.

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  • Thin, translucent, and lacking enamel as well as dentine, these modern structures are known as cycloid and ctenoid scales.

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  • Thin, translucent, and lacking enamel as well as dentine, these modern structures are known as cycloid and ctenoid scales.

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  • Thin, translucent, and lacking enamel as well as dentine, these modern structures are known as cycloid and ctenoid scales.

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  • The fine-grained assemblage is dominated by tabular, low-density elements, such as cycloid scales and fish vertebrae.

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  • The fine-grained assemblage is dominated by tabular, low-density elements, such as cycloid scales and fish vertebrae.

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  • A curve described in space by a point of a circle or sphere, which itself is carried along at the same time, is some kind of cycloid; if the centre of the tracing circle travels along a straight line, we get the ordinary cycloid, the curve traced in air by a nail on a coach-wheel; but if the centre of the tracing circle be carried round another circle the curve described is called an epicycloid.

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Comments

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  • Used in the sense of 'manic-depressive' in some literature.

    April 24, 2011