(A) Treated as plural. The twelve signs of the zodiac. (b) With singular concord. The star Sirius; (also) the constellation Canis Major (which contains Sirius). Also (occasionally) applied to other individual stars or constellations.
Mid 16th century; earliest use found in The Bible and Holy Scriptures. From Hebrew mazzārōṯ, plural of mazzār constellation, zodiac (only Job 38:32 in plural), probably variant of mazzāl star.