(the Ram; abbrev. Ari, gen. Arietis; area 441 sq. deg.) A northern zodiacal constellation that lies between Taurus and Pisces, and culminates at midnight in late October. It represents the ram in Greek mythology whose golden fleece was the quest of Jason and the Argonauts. Its brightest stars were cataloged by Ptolemy (c. AD 100–175) in the Almagest