Definition of primum mobile in English:

primum mobile

noun

  • 1The most important source of motion or action.

    • ‘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.’
    • ‘He is, in essence, the primum mobile: he wrote Aaron's program, but Aaron now produces its original paintings without Cohen's intervention.’
  • 2(in the medieval version of the Ptolemaic system) an outer sphere supposed to move round the earth in twenty-four 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.’
    • ‘The drawings show the Ptolemaic system of nested spheres, with one circle inside the other, ending in the Primum Mobile.’
    • ‘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.’

Origin

From medieval Latin, literally first moving thing.

Pronunciation:

primum mobile

/ˌprʌɪməm ˈməʊbɪleɪ//ˌpriːməm ˈməʊbɪli/