The constellation Ursa Major (the Great Bear), referred to in Job 9:9 and 38:32 (in the King James Version). It is mentioned in connection with the constellation Orion and the Pleiades. See Astronomy.
[Editor's note: Arcturus is actually a star in the constellation Boötes, which is near the constellation Ursa Major.]
Arcturus
From Tyndale Bible Dictionary, adapted by Mission Mutual. CC BY-SA 4.0.