shorten vs bring down

shorten and bring down both are verbs.

Word	Noun	Adjective	Verb	Adverb
shorten	No	No	Yes	No
bring down	No	No	Yes	No

As verbs, bring down is a hypernym of shorten; that is, bring down is a word with a broader meaning than shorten:

shorten: make shorter than originally intended; reduce or retrench in length or duration
bring down: cut down on; make a reduction in

Other hypernyms of shorten include cut, cut back, cut down, reduce, trim, trim back, trim down.

shorten (verb)	bring down (verb)
become short or shorter	cut down on; make a reduction in
make shorter than originally intended; reduce or retrench in length or duration	impose something unpleasant
reduce in scope while retaining essential elements	cause to be enthusiastic
edit by omitting or modifying parts considered indelicate	cause to come to the ground
make short or shorter	move something or somebody to a lower position
	cause the downfall of; of rulers