Cycloid

Part of speech: noun (n.)

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.

Part of speech: noun (n.)

One of the Cycloidei.

Part of speech: adjective (a.)

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.