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. [1913 Webster]

" The common cycloid is the curve described when the generating point (p) is on the circumference of the generating circle; the curtate cycloid, when that point lies without the circumference; the prolate or inflected cycloid, when the generating point (p) lies within that circumference." [1913 Webster]

Cycloid, a.

Of or pertaining to the Cycloidei. [1913 Webster]

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

Cycloid, n.

One of the Cycloidei. [1913 Webster]

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OXFORD DICTIONARY

Cycloid, n. Math. a curve traced by a point on a circle when the circle is rolled along a straight line.

Derivative

cycloidal adj.

Etymology

Gk kukloeides (as CYCLE, -OID)

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ROGET THESAURUS

Cycloid

Circularity

N circularity, roundness, rotundity, circle, circlet, ring, areola, hoop, roundlet, annulus, annulet, bracelet, armlet, ringlet, eye, loop, wheel, cycle, orb, orbit, rundle, zone, belt, cordon, band, contrate wheel, crown wheel, hub, nave, sash, girdle, cestus, cincture, baldric, fillet, fascia, wreath, garland, crown, corona, coronet, chaplet, snood, necklace, collar, noose, lasso, lassoo, ellipse, oval, ovule, ellipsoid, cycloid, epicycloid, epicycle, semicircle, quadrant, sextant, sector, sphere, round, rounded, circular, annular, orbicular, oval, ovate, elliptic, elliptical, egg-shaped, pear-shaped, cycloidal, spherical, I watched the little circles die.

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