plural primum mobiles
Definition of primum mobile
: the outermost concentric sphere conceived in medieval astronomy as carrying the spheres of the fixed stars and the planets in its daily revolution
Keep scrolling for more
Love words? Need even more definitions?Merriam-Webster unabridged
Words at Play
Ask the Editors
- Why Do People Pronounce It "Nucular"?
- On Contractions of Multiple Words
- Is Singular 'They' a Better Choice?
- Word Puzzles Take the quiz
- Where in the World? A Quiz Take the quiz
- Spell It Take the quiz
- Dictionary Devil Play the game