| on | a sixth part |
|---|---|
| on | an early ballroom dance |
| on | a tenth part |
| on | one of three equal parts of a divisible whole |
| on | one part in a thousand |
| on | one part in a trillion |
| on | the practice of keeping one jump ahead of a friend or competitor |
| on | permitting movement or travel in one direction only |
| on | the elapsed time it takes for light (or radio signals) to travel between the Earth and a celestial object |
| on | a street on which vehicular traffic is allowed to move in only one direction |
| on | designed for or restricted to a single person |
| on | (botany) completing its life cycle within a year |