Open main menu

Writing star.svg

Word of the day for December 18
primum mobile n
  1. (astronomy, historical) The outermost celestial sphere of the heavens in Ptolemaic astronomy, which was believed to cause all the inner spheres to rotate.
  2. (chiefly philosophy, theology) The prime mover or first cause (an initial cause from which all other causes and effects follow).
  3. (by extension) The person or thing that is the main impetus for some action; a driving force.

PointingHand.svg Today is UN Arabic Language Day, one of six such days established by UNESCO to celebrate multilingualism and cultural diversity and to promote the equal use of its working languages. The term primum mobile is a calque of Arabic مُحَرِّك أَوَّل(muḥarrik ʾawwal, literally first mover).

← yesterday | About Word of the DayArchiveNominate a wordLeave feedback | tomorrow →