single flower; one bloom
Refers to a single flower or blossom, often in poetic or descriptive contexts.
A single rose is arranged in the vase.
one wheel
Used for a single wheel, e.g., of a vehicle or machine.
A unicycle balances on just one wheel.
Poetic term for the full moon; not used in everyday conversation.
一輪の花が道端に咲いていた。
A single flower was blooming by the roadside.
The harvest moon is also called a full moon (一輪の月).
Compound of 一 (one) and 輪 (ring, wheel, flower). The 'full moon' sense is a poetic extension likening the moon to a single round flower or wheel.