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Related to cycloidal: Cycloidal propeller
click for a larger image
top: surface view of cycloid scales of a bony fish
bottom: The parametric equations of this cycloid are
x = r(θ - sin θ),
y = r(1 - cos θ).
click for a larger image


1. Resembling a circle.
2. Zoology
a. Relating to or being a kind of fish scale that is thin, rounded, and smooth-edged and often shows concentric growth rings.
b. Having cycloid scales.
3. Psychology Afflicted with or relating to cyclothymia.
n. Mathematics
The curve traced by a point on the circumference of a circle that rolls on a straight line.

[French cycloïde, from Greek kukloeidēs, circular : kuklos, circle; see kwel- in Indo-European roots + -oeidēs, -oid.]

cy·cloi′dal (-kloid′l) adj.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Adj.1.cycloidal - resembling a circle
rounded - curving and somewhat round in shape rather than jagged; "low rounded hills"; "rounded shoulders"
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
References in periodicals archive ?
It is considered that the accumulated pore of a differential element of mortar produced by the chemical action can be obtained through the rotation of the cycloidal equation.
To improve the performance of the power generation system, which consisted of several blades rotating about axis in parallel direction, the cycloidal blade system and the individual active blade control system were adopted, respectively.
The failure diagnostic problems of vertical axis rotating machine driven by ten cycloidal gear reducers is complicated from practical diagnostics point of view using vibration monitoring parameters [1].
Zhang, "Investigation of unsteady aerodynamics effects in cycloidal rotor using RANS solver," Aeronautical Journal, vol.
Besides general involute planetary gears, scholars have also researched dynamics of cycloidal planetary gears.
Jiang, "Optimal design of an axial-flux permanent-magnet middle motor integrated in a cycloidal reducer for a pedal electric cycle," Energies, vol.
[17.] Littera D., Nickerson M., Kopache A., Machamada G., Sun C, Schramm A., Medeiros N, Becker K., Shkolnik S., and Shkolnik A., "Development of the XMv3 High Efficiency Cycloidal Engine," SAE Technical Paper 2015-32-0719, 2015.
Shock load resistant, cost-effective and easily mounted, planetary and cycloidal gearheads now include models up to a NEMA 256 and custom units can be produced to IEC specs.
She is also qualified to offer services such as cold laser therapy, soft tissue deep oscillation and cycloidal vibration therapy, which all help to improve the healing of injuries and wounds.
Splined screw shafts utilize a cycloidal profile ensuring effective torque transmission with increased fracture resistance while facilitating easy removal of the elements for maintenance and reconfiguration.