cycloid

1 of 2

noun

cy·​cloid ˈsī-ˌklȯid 

: a curve that is generated by a point on the circumference of a circle as it rolls along a straight line

cycloidal

sī-ˈklȯi-dᵊl 

adjective

Illustration of cycloid

cycloid

2 of 2

adjective

1

: smooth with concentric lines of growth

cycloid scales

also : having or consisting of cycloid scales

2

: characterized by alternating high and low moods

a cycloid personality

Examples of cycloid in a Sentence

Recent Examples on the Web

Noun

Phantom, a Silicon Valley humanoid robot startup, is already manufacturing its own proprietary cycloid actuators. — John Koetsier, Forbes.com, 17 June 2026

The fish has a scaleless head with small, cycloid scales on the body and belly, according to the study. — Irene Wright, Miami Herald, 12 Feb. 2025

The solution is a cycloid, which is the curve created by a rolling wheel in a circle. — Jennifer Ouellette, Ars Technica, 17 May 2020

Word History

Etymology

Noun

French cycloïde, from Greek kykloeidēs circular, from kyklos

First Known Use

Noun

1661, in the meaning defined above

Adjective

1847, in the meaning defined at sense 1

Rhymes for cycloid

• alloyed
• android
• annoyed
• avoid
• convoyed
• crinoid
• cuboid
• decoyed
• deployed
• dermoid
• destroyed
• devoid

Kids Definition

cycloid

noun

cy·​cloid

ˈsī-ˌklȯid

: a curve that is traced by a point on the circumference of a circle that is rolling along a straight line

Medical Definition

cycloid

1 of 2 noun

cy·​cloid ˈsī-ˌklȯid 

: a cycloid individual

cycloid

2 of 2 adjective

: relating to, having, or being a personality characterized by alternating high and low moods compare cyclothymic