Rank - Some lists of the brightest stars may have a slightly different order because some of the brightest stars are variable stars whose magnitudes change. Betelgeuse, for example, may have varied from magnitude 0.2 to 1.2 historically. Its brightness may have rivaled that of Rigel, which may be why Johannes Bayer gave it an alpha designation in Uranometria in 1603.
Visual Magnitude - This is the apparent visual magnitude of the star. Lower numbers mean brighter stars. Stars with negative magnitude numbers are the brightest. Note that the magnitude scale is logarithmic with each magnitude being 2.512 times brighter than the next.
Distances are given in light-years and light-minutes. A light-year (ly) is the distance light travels in one year - about 6 trillion miles (10 trillion kilometers). A light-minute (lm) is the distance light travels in one minute - about 11 million miles (17 million kilometers). The distance from the Earth to the Sun is about of 93 million miles (150 million kilometers) or about 8.3 light minutes.
Distances to the closer stars are fairly accurate as they have been measured by parallax by the Hipparcos satellite. Distances to farther stars are more uncertain. In some cases for these stars the uncertainty can be quite substantial. For example, the distance to Deneb is estimated to be between 1,425 light-years to 2,615 light-years.
The Sun's brightness is fairly constant, but varies by about 0.1 percent over its 11-year sunspot cycle. Almost all stars may be found to be variable if they could be measured accurately to this level of precision. Some variable stars, however, have very large brightness ranges.
Variable star status is from the AAVSO International Variable Star Index.