unicycle

American  

[yoo-nuh-sahy-kuhl] / ˈyu nəˌsaɪ kəl /

noun

1. a vehicle with one wheel, especially a pedal-driven device kept upright and steered by body balance, commonly used by acrobats and other performers.

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verb (used without object)

unicycled, unicycling

1. to ride a unicycle.

unicycle British  

/ ˈjuːnɪˌsaɪkəl /

noun

1. Also called: monocycle.  a one-wheeled vehicle driven by pedals, esp one used in a circus, etc

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Other Word Forms

Derived Forms

• unicyclist
  noun

Etymology

Origin of unicycle

An Americanism dating back to 1865–70; uni- + cycle

Explanation

You might see a unicyle, or a bicycle-like vehicle with only one wheel, ridden by a clown at the circus. It's harder to ride a unicycle than a bicycle, since you have to balance on a single wheel. Acrobats and other performers often ride unicycles and sometimes even do tricks like balancing on a tightrope while perched on the seat of a unicycle. The Latin prefix uni gives you a clue about the meaning of this word, since it means "one." In unicycle, it's combined with "cycle," which comes from the Greek word kyklos, "circle or wheel."

Example Sentences

A man on a unicycle brandished a sign, inspired by J.R.R.

From The Wall Street Journal • Feb. 8, 2026

He can go out to his shed, look at the unicycle he hasn’t used for three years and know that someday he’ll give it another go.

From Los Angeles Times • Jun. 17, 2024

One study found that participants were half as likely to notice a clown on a unicycle — a cheeky touch — while walking and talking on a phone.

From Seattle Times • Jan. 28, 2024

To operate an electric unicycle, the rider stands on it and leans in order to accelerate, brake and steer.

From BBC • Jul. 24, 2023

And so we watched it all: the eighteen-year-old boy with a fake mustache who did a magic show and juggled flaming hoops while riding a unicycle.

From "The Joy Luck Club" by Amy Tan