Origin of cycloidClassical Greek kykloeid?s, circular ; from kyklos (see wheel) + -eid?s, -oid
- designating or having fish scales that are roundish in form with smooth edges
- designating or of a cyclothymic person
- Resembling a circle.
- 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.
- Psychology Afflicted with or relating to cyclothymia.
Origin of cycloidFrench cyclo&idie;de, from Greek kukloeid&emacron;s, circular : kuklos, circle; see kwel-1 in Indo-European roots + -oeid&emacron;s, -oid.
top: surface view of cycloid scales of a bony fish
bottom: The parametric equations of this cycloid are
x = r(&thgr; - sin &thgr;),
y = r(1 - cos &thgr;).
cyclo- + -oid