EASTON’S BIBLE DICTIONARY (1897 EDITION)
Arcturus – bear-keeper, the name given by the ancients to the brightest star in the constellation Bootes.
In the Authorized Version (Job 9:9; 38:32) it is the rendering of the Hebrew word ‘ash, which probably designates the constellation the Great Bear.
This word (‘ash) is supposed to be derived from an Arabic word meaning night-watcher, because the Great Bear always revolves about the pole, and to our nothern hemisphere never sets.