/ Dictionary / Index J Jansen: Meaning and Definition of Find definitions for: Jan•sen Pronunciation: ( jan'sun Du. yän'sun), [key] (Cornelius Jansenius), 1585–1638, Dutch Roman Catholic theologian. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: jansen (Thesaurus) jannock Jansenism Related Content Daily Word Quiz: inutiae Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language