coffin vs box

coffin and box both are nouns.

Word	Noun	Adjective	Verb	Adverb
coffin	Yes	No	Yes	No
box	Yes	No	Yes	No

As nouns, box is a hypernym of coffin; that is, box is a word with a broader meaning than coffin:

coffin (noun)	box (noun)
box in which a corpse is buried or cremated	a blow with the hand (usually on the ear)
	a (usually rectangular) container; may have a lid
	separate partitioned area in a public place for a few people
	private area in a theater or grandstand where a small group can watch the performance
	the driver's seat on a coach
	any one of several designated areas on a ball field where the batter or catcher or coaches are positioned
	evergreen shrubs or small trees
	the quantity contained in a box
	a rectangular drawing
	a predicament from which a skillful or graceful escape is impossible