/ Dictionary / Index P primum mobile*: Meaning and Definition of Find definitions for: pri•mum mo•bi•le Pronunciation: (prē'moom mō'bi-le" Eng. prī'm&schwam mob'&schwa-lē", prē'-), [key] — Latin. Latin. (in Ptolemaic astronomy) the outermost of the 10 concentric spheres of the universe, making a complete revolution every 24 hours and causing all the others to do likewise. See Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. primulaceous primus Related Content Daily Word Quiz: cygnet Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language