Definition of primum mobile in English:

primum mobile


  • 1The central or most important source of motion or action.

    • ‘He is, in essence, the primum mobile: he wrote Aaron's program, but Aaron now produces its original paintings without Cohen's intervention.’
    • ‘He thinks that Legallois, Flourens and Charles Bell are "equally in error, when they considered the medulla oblongata as the lauree, the primum mobile, of the respiratory motions."’
    • ‘So I could not but think that these puppet-like motions might, with a little ingenuity have been produced by the great water wheel, which is the primum mobile of the whole Cotton-Mills.’
  • 2(in the medieval version of the Ptolemaic system) an outer sphere supposed to move around the earth in 24 hours, carrying the inner spheres with it.

    • ‘Aristotle posited that the heavens contained 55 spheres, with the Primum Mobile, "Prime Mover" or "First Moveable", giving motion to all the spheres within it.’
    • ‘Sacrobosco's ‘last heaven’ was the sphere of the primum mobile, which meant literally that it was the ‘first moved’, the origin of movement that mechanically transmitted regular motion to all the other spheres.’
    • ‘The drawings show the Ptolemaic system of nested spheres, with one circle inside the other, ending in the Primum Mobile.’


From medieval Latin, literally ‘first moving thing’.


primum mobile

/ˌprīməm ˈmōbəˌlē/