/ Dictionary / Index L life jacket: Meaning and Definition of Find definitions for: life' jack"et Pronunciation: [key] a sleeveless jacket of buoyant or inflatable construction, for supporting the wearer in deep water and preventing drowning. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. life interest lifeless Related Content Daily Word Quiz: neologism Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language