Definitions

1. noun

a vehicle with a single wheel, ridden by one person sitting astride it, and controlled by balancing and steering

“She practiced riding a unicycle in the empty parking lot.”

2. noun

a device consisting of a single wheel, for display or demonstration, often as a prop in a circus or theatrical performance

“The circus performer expertly balanced on the elaborate unicycle.”

3. verb

to ride a unicycle

“He unicycled across the tightrope high above the audience.”