An Etymological Dictionary of Astronomy and Astrophysics

The excess of the equatorial diameter over the polar diameter of a celestial object, such as the Earth or the Moon.

Etymology (EN): → equatorial; bulge, from O.Fr. bouge “leather bag,” from L. bulga “leather bag,” of Gaulish origin.

Etymology (PE): Barâmadegi, from barâmadan “to grow out; to emerge,” from bar- “on, upon, up” (Mid.Pers. abar, O.Pers. upariy “above; over, upon, according to,” Av. upairi “above, over,” upairi.zəma- “located above the earth;” cf. Gk. hyper- “over, above;” L. super-; O.H.G. ubir “over;” PIE base *uper “over”) + âmadan “to come” (Mid.Pers. âmadan;
O.Pers. gam- “to come; to go;” Av. gam- “to come; to go,” jamaiti “goes;”
cf. Skt. gamati “goes;” Gk. bainein “to go, walk, step;” L. venire “to come;” Tocharian A käm- “to come;” O.H.G. queman “to come;” E. come; PIE root *gwem- “to go, come”).