In the Ptolemaic system, the outermost of the revolving concentric spheres constituting the universe, the motion of which was supposed to carry with it all the inclosed spheres with their planets in a daily revolution from east to west. See Crystalline heavens, under Crystalline.
Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). primum mobile. Retrieved September 23, 2026, from http://smartdefine.org/primum_mobile/definitions/2049241 |
| Chicago | Webster's. 2011. "primum mobile" http://smartdefine.org/primum_mobile/definitions/2049241 (accessed September 23, 2026). |
| Harvard | Webster's 2011, primum mobile, Smart Define, viewed 23 September, 2026, <http://smartdefine.org/primum_mobile/definitions/2049241>. |
| MLA | Webster's. "primum mobile" 27 May 2011. Web. 23 September 2026. <http://smartdefine.org/primum_mobile/definitions/2049241> |