/ Dictionary / Index P prime number theorem: Meaning and Definition of Find definitions for: prime' num'ber the"orem Pronunciation: [key] — Math. Math. the theorem that the number of prime numbers less than or equal to a given number is approximately equal to the given number divided by its natural logarithm. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. prime number primer Related Content Daily Word Quiz: feline Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language