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 cycloïde from Greek kukloeidēs circular kuklos circle ; see kwel-1 in Indo-European roots. -oeidēs -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