chest vs sea chest

chest and sea chest both are nouns.

Word	Noun	Adjective	Verb	Adverb
chest	Yes	No	No	No
sea chest	Yes	No	No	No

As nouns, sea chest is a hyponym of chest; that is, sea chest is a word with a more specific, narrower meaning than chest:

chest (noun)	sea chest (noun)
box with a lid; used for storage; usually large and sturdy	a sailor's storage chest for personal property
furniture with drawers for keeping clothes
the part of the human torso between the neck and the diaphragm or the corresponding part in other vertebrates
the front of the trunk from the neck to the abdomen