Scorpio
in astronomy, the eighth zodiacal constellation. It is bounded on the N. by Ophiuchus and Serpens, on the S. by Lupus, Norma, and Ara, on the E. by Sagittarius, and on the W. by Libra.
It is a small but very brilliant constellation, especially when seen from places S. of the equator. It contains Antares or Cor Scorpii (Alpha Scorpii), of the first magnitude, and Iklil, or Beta Scorpii, of the second magnitude. Also the eighth sign of the zodiac, which the sun enters about Oct. 23.