Entomology definition of Arcus September 7, 2014 Raj Entomology Dictionary 0 Please Like Us!!! DesiGoogly.com > Education News > Entomology Dictionary > Entomology definition of Arcus Entomology definition of Arcus: a bow; part of a circle; but less than one half. Arcus Entomology explanationArcus Entomology meaningEntomology Arcus definitionReviews & Comments