(Latin: Lion), in astronomy, zodiacal constellation lying between Cancer and Virgo, at about 10 hours 30 minutes right ascension (the coordinate of the celestial sphere analogous to longitude on the Earth) and 15° north declination (angular distance north of the celestial equator). Regulus (Alpha Leonis), the brightest star, is of the first magnitude. The November meteor shower called the Leonid has its radiant, or point of apparent origin, in Leo.