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Of or pertaining to the Cycloidei. Cycloid scale (Zoöl.), a fish scale which is thin and shows concentric lines of growth, without serrations on the margin.

Pertaining to, or resembling, a cycloid; as, the cycloidal space is the space contained between a cycloid and its base. Cycloidal engine. See Geometric lathe.

An order of fishes, formerly proposed by Agassiz, for those with thin, smooth scales, destitute of marginal spines, as the herring and salmon. The group is now regarded as artificial.

Same as 2d and 3d Cycloid.

A curve traced by a point in the circumference of a circle which rolls on the convex side of a fixed circle.

Pertaining to the epicycloid, or having its properties. Epicycloidal wheel, a device for producing straight-line motion from circular motion, on the principle that a pin fastened in the periphery of a gear wheel will describe a straight line when the wheel rolls around inside a fixed internal gear of twice its diameter…

the circumference of a circle which rolls on the concave side in the fixed circle. Cf. Epicycloid, and Trochoid.

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

lar, let fall from the planet upon the plane of the ecliptic, meets the ecliptic. Curtate cycloid. (Math.) See Cycloid.

An order of ganoid fishes, having cycloid scales. The bowfin (Amia calva) is a living example.

A kind of curve. See Epicycloid, any Trochoid.

sma. Many of the species are covered with bony plates, or with ganoid scales; others have cycloid scales.

radius produced, of a circle which rolls upon the concave side of a fixed circle. See Hypocycloid, Epicycloid, and Trochoid.

Having inflections; capable of, or subject to, inflection; inflective. Inflected cycloid (Geom.), a prolate cycloid. See Cycloid.

ection of a line joining the poles; as, a prolate spheroid; -- opposed to oblate. Prolate cycloid. See the Note under Cycloid. -- Prolate ellipsoid or spheroid (Geom.), a figure generated by the revolution of an ellipse about its major axis. See Ellipsoid of revolution, under Ellipsoid.

ne of a given curve when the latter rolls, without sliding, over another fixed curve. See Cycloid, and Epycycloid.

es, and some mammals, belonging to the dermal part of the skeleton, or dermoskeleton. See Cycloid, Ctenoid, and Ganoid. Fish that, with their fins and shining scales, Glide under the green wave. Milton.

owest point in the same time, wherever in the curve it may begin to fall; as, an inverted cycloid with its base horizontal is a tautochrone.

The curve described by any point in a wheel rolling on a line; a cycloid; a roulette; in general, the curve described by any point fixedly connected with a moving curve while the moving curve rolls without slipping on a second fixed curve, the curves all being in one plane. Cycloids, epicycloids, hypocycloids, cardioid…