life vest vs life jacket

life vest and life jacket both are nouns.

Word	Noun	Adjective	Verb	Adverb
life vest	Yes	No	No	No
life jacket	Yes	No	No	No

As nouns, life vest and life jacket are synonyms defined as:

life vest and life jacket: life preserver consisting of a sleeveless jacket of buoyant or inflatable design

Other synonyms of life vest include cork jacket.

life vest (noun)	life jacket (noun)
life preserver consisting of a sleeveless jacket of buoyant or inflatable design	life preserver consisting of a sleeveless jacket of buoyant or inflatable design