(Science: anatomy) a fixed star of the first magnitude in the constellation bootes.
arcturus has sometimes been incorrectly used as the name of the constellation, or even of ursa major. Canst thou guide arcturus with his sons [Rev. Ver., the bear with her train] (job xxxviii. 32)
Origin: L. Arcturus, gr. Bearward, equiv. To; bear _ ward, guard. See arctic.