[yoo-nuh-sahy-kuh
l] 
noun, verb, -cled, -cling.| 1. | a vehicle with one wheel, esp. a pedal-driven device kept upright and steered by body balance, commonly used by acrobats and other performers. |
| 2. | to ride a unicycle. |
| u·ni·cy·cle (yōō'nĭ-sī'kəl) n. A vehicle consisting of a frame mounted over a single wheel and usually propelled by pedals. [uni- + -cycle, perhaps on the model of bicycle.] u'ni·cy'clist n. |