chains vs shackle

chains and shackle both are nouns.

Word	Noun	Adjective	Verb	Adverb
chains	Yes	No	No	No
shackle	Yes	No	Yes	No

As nouns, shackle is a hypernym of chains; that is, shackle is a word with a broader meaning than chains:

chains: metal shackles; for hands or legs
shackle: a restraint that confines or restricts freedom (especially something used to tie down or restrain a prisoner)

Other hypernyms of chains include bond, hamper, trammel.

chains (noun)	shackle (noun)
metal shackles; for hands or legs	a restraint that confines or restricts freedom (especially something used to tie down or restrain a prisoner)
	a U-shaped bar; the open end can be passed through chain links and closed with a bar

chains (verb)	shackle (verb)
	restrain with fetters
	bind the arms of