/ Dictionary / Index P Paschen series: Meaning and Definition of Find definitions for: Pa'schen se"ries Pronunciation: (pä'shun), [key] — Physics. Physics. a series of lines in the infrared spectrum of hydrogen. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Paschen-Back effect Pascin Related Content Daily Word Quiz: secular Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language