CYCLOID

cycloid, cycloidal

(adjective) resembling a circle

cycloid

(noun) a line generated by a point on a circle rolling along a straight line

Source: WordNet® 3.1

Etymology

Noun

cycloid (plural cycloids)

(geometry) The locus of a point on the circumference of a circle that rolls without slipping on a fixed straight line.

(zoology) A fish having cycloid scales.

Adjective

cycloid (not comparable)

Resembling a circle; cycloidal.

(zoology, of fish scales) Thin and rounded, with smooth edges.

(psychoanalysis)

Source: Wiktionary

Cy"cloid (s"kloid), n. Etym: [Cyclo- + -oid: cf. F. cycloïde.] (Geom.)

Definition: 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.

Cy"cloid, a. (Zoöl.)

Definition: 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.

Cy"cloid, n. (Zoöl.)

Definition: One of the Cycloidei.

Source: Webster’s Unabridged Dictionary 1913 Edition