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.

---

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

---

Other Word 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

She has since been a staple at NBA games and numerous other athletic events, with her signature routine of using her feet to flip bowls onto her head while balancing high on her unicycle.

From Los Angeles Times • Jul. 2, 2025

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

He walks toward me smiling and holding a framed painting of an old-timey clown on a unicycle.

From "I Am Not Your Perfect Mexican Daughter" by Erika L. Sánchez