/ Dictionary / Index P primary beam: Meaning and Definition of Find definitions for: pri'mary beam" Pronunciation: [key] — Physics. Physics. See under Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. primary accent primary care Related Content Daily Word Quiz: immense Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language