Defn: 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.
Note: 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.
CYCLOID
Cy"cloid, a. (Zoöl.)
Defn: 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.
CYCLOID
Cy"cloid, n. (Zoöl.)
Defn: One of the Cycloidei.
CYCLOIDAL
Cy*cloid"al (-al), a.
Defn: 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.
CYCLOIDEI
Cy*cloi"de*i (s-kloi"d-), n. pl. Etym: [NL., fr. Gr. -oid.] (Zoöl.)
Defn: 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.