/ Dictionary / Index S second mortgage: Meaning and Definition of Find definitions for: sec'ond mort'gage Pronunciation: [key] a mortgage the lien of which is next in priority to a first mortgage. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. second messenger second nature Related Content Daily Word Quiz: hedonist Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language