a wheeled vehicle that has two wheels and is moved by foot pedals | (astronomy) the particular appearance of a body's state of illumination (especially one of the recurring shapes of the part of Earth's moon that is illuminated by the sun) |
a single complete execution of a periodically repeated phenomenon | (physical chemistry) a distinct state of matter in a system; matter that is identical in chemical composition and physical state and separated from other material by the phase boundary |
a periodically repeated sequence of events | any distinct time period in a sequence of events |
a series of poems or songs on the same theme | a particular point in the time of a cycle; measured from some arbitrary zero and expressed as an angle |
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) | |