cycloid

[ sahy-kloid ]
/ ˈsaɪ klɔɪd /

adjective

resembling a circle; circular.
(of the scale of a fish) smooth-edged, more or less circular in form, and having concentric striations.
(of a fish) having such scales.
Psychiatry. of or noting a personality type characterized by wide fluctuation in mood within the normal range.

noun

a cycloid fish.
Geometry. a curve generated by a point on the circumference of a circle that rolls, without slipping, on a straight line.

Origin of cycloid

First recorded in 1655–65, cycloid is from the Greek word kykloeidḗs like a circle. See cycl-, -oid

OTHER WORDS FROM cycloid

cy·cloi·dal, adjective cy·cloi·dal·ly, adverb

Words nearby cycloid

cyclohexane, cyclohexanone, cycloheximide, cyclohexylamine, cyclohexylsulfamic acid, cycloid, cycloidal propulsion, cyclolysis, cyclometer, cyclonal, cyclone

Example sentences from the Web for cycloid

British Dictionary definitions for cycloid

cycloid
/ (ˈsaɪklɔɪd) /

adjective

resembling a circle
(of fish scales) rounded, thin, and smooth-edged, as those of the salmon
psychiatry (of a type of personality) characterized by exaggerated swings of mood between elation and depression See also cyclothymia

noun

geometry the curve described by a point on the circumference of a circle as the circle rolls along a straight line Compare trochoid (def. 1)
a fish that has cycloid scales

Derived forms of cycloid

cycloidal, adjective cycloidally, adverb

Scientific definitions for cycloid

cycloid
[ sī′kloid′ ]

Resembling a circle.
Thin, rounded, and smooth-edged, like a disk. Used of fish scales.
The curve traced by a point on the circumference of a circle that rolls on a straight line.