/ Dictionary / Index S Sister of Mercy: Meaning and Definition of Find definitions for: Sis'ter of Mer'cy Pronunciation: [key] — Rom. Cath. Ch. Rom. Cath. Ch. a member of a congregation of sisters founded in Dublin in 1827 by Catherine McAuley (1787–1841) and engaged chiefly in works of spiritual and corporal mercy. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Sister of Loretto Sistine Related Content Daily Word Quiz: philtrum Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language