An Etymological Dictionary of Astronomy and Astrophysics

A spherical or approximately spherical body, either solid or hollow.

Etymology (EN): From M.E. bal, balle, from O.Fr.; cf. O.H.G. ballo, Ger. Ball; PIE root *bhel- “to blow, swell.”

Etymology (PE): Tup “ball,” initially “clmup, aggregation, parcel, group” (tup tup “many”); Tabari tupa “compressed, assembled,” tuppi “round;” Kurd. top “ball,” topâl “round;”
guy, → globe.