three wheels; tricycle
Refers to a vehicle or object with three wheels. Often used in compounds like 三輪車 (tricycle).
The child is riding a tricycle.
三輪 refers to something with three wheels (like a tricycle), while 四輪 refers to a four-wheeled vehicle (like a car), so the two are easily confused when discussing wheel count.
三輪 means three-wheeled (e.g. a tricycle), whereas 二輪 means two-wheeled (e.g. a motorcycle or bicycle), so learners may mix up which number goes with which vehicle type.
Compound of 三 (three) and 輪 (wheel).