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| Symbol | Definition |
|---|---|
| ≡ | exactly equal |
| ≈ | approximately equal to |
| = | equal to |
| digits | indicates that digits repeat infinitely (e.g. 8.294 369 corresponds to 8.294 369 369 369 369 …) |
In typography, the stick, stickful, or stick of type was an inexact length based on the size of the various composing sticks used by newspaper editors to assemble pieces of moveable type. In English-language papers, it was roughly equal to 2 column inches or 100–150 words. In France, Spain, and Italy, sticks generally contained only between 1 and 4 lines of text each. A column was notionally equal to 10 sticks.
The astronomical unit (symbol: au or ua) is a unit of length, roughly the distance from Earth to the Sun. However, that distance varies as Earth orbits the Sun, from a maximum (aphelion) to a minimum (perihelion) and back again once a year. Originally conceived as the average of Earth's aphelion and perihelion, it is now defined as exactly 149 597 870 700 metres (about 150 million kilometres, or 93 million miles). The astronomical unit is used primarily as a convenient yardstick for measuring distances within the Solar System or around other stars. However, it is also a fundamental component in the definition of another unit of astronomical length, the parsec.