Also found in: Thesaurus, Medical, Encyclopedia, Wikipedia.
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.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Adj.1.cycloidal - resembling a circle
rounded - curving and somewhat round in shape rather than jagged; "low rounded hills"; "rounded shoulders"
References in periodicals archive ?
Tenders are invited for Hire Of One Number (Tractor/Reverse Tractor Of Cycloidal Or Steerable Rudder Propulsion System Inclusive Of Azimuth Stern Drive) Harbour Tug Of Bollard Pull 50 Ton Or More At 100 For 07 Years To Mormugao Port Trust
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].
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.
Powered by either twin Azimuthing drives (an eggbeater-like propeller in a housing that can spin 360 degrees) or twin Voith Schneider propellers (a cycloidal drive driven by vertical blades), the tugs can spin on a dime.
The topics include recent research on magnesium alloy melting technology, abrasive flow machining for the outer rotor of a cycloidal pump, the dynamic analysis of the leveling mechanism of a new goose-neck jib gondola, simulation research on the climbing ability of a shovel loader with four tracks, and a piezoelectric energy harvester for wireless sensors.
Generally the trajectory of the swing foot of human is a cycloidal profile in normal walking (5).
Thus the Stokes solution to the wave equation should be included to describe the cycloidal movement of the water particles.