Cassius is somewhat popular as a baby name for boys. The name's popularity has been increasing since the 2010s. At the modest height of its usage in 2011, 0.012% of baby boys were given the name Cassius. Its ranking then was #876.In 2012, its usage was 0.011% and its ranking #928.assius is somewhat popular as a baby name for boys. The name's popularity has been increasing since the 2010s. At the modest height of its usage in 2011, 0.012% of baby boys were given the name Cassius. Its ranking then was #876.