a large, rotating machine with seats for children to ride on for amusement | a wheeled vehicle that has two wheels and is moved by foot pedals |
a never-ending cycle of activities and events (especially when they seem to have little purpose) | a single complete execution of a periodically repeated phenomenon |
| a periodically repeated sequence of events |
| a series of poems or songs on the same theme |
| an interval during which a recurring sequence of events occurs |
| the unit of frequency; one hertz has a periodic interval of one second (named for Heinrich Rudolph Hertz) |