preserver vs flotation device

preserver and flotation device both are nouns.

Word	Noun	Adjective	Verb	Adverb
preserver	Yes	No	No	No
flotation device	Yes	No	No	No

As nouns, preserver and flotation device are synonyms defined as:

preserver and flotation device: rescue equipment consisting of a buoyant belt or jacket to keep a person from drowning

Other synonyms of preserver include life preserver.

preserver (noun)	flotation device (noun)
rescue equipment consisting of a buoyant belt or jacket to keep a person from drowning	rescue equipment consisting of a buoyant belt or jacket to keep a person from drowning
a skilled worker who is employed to restore or refinish buildings or antique furniture
someone who keeps safe from harm or danger
a cook who preserves fruits or meat