the distance between things | a wheeled vehicle that has two wheels and is moved by foot pedals |
a set containing all points (or all real numbers) between two given endpoints | a single complete execution of a periodically repeated phenomenon |
the difference in pitch between two notes | a periodically repeated sequence of events |
a definite length of time marked off by two instants | 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) |