/ Dictionary / Index S secondary beam: Meaning and Definition of Find definitions for: sec'ondary beam" Pronunciation: [key] — Physics. Physics. a beam of particles of one kind selected from the group of particles produced when a beam of particles from an acceleratorstrikes a target. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. secondary articulation secondary boycott Related Content Daily Word Quiz: procrastinate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language