tax shelter vs reduction

tax shelter and reduction both are nouns.

Word	Noun	Adjective	Verb	Adverb
tax shelter	Yes	No	No	No
reduction	Yes	No	No	No

As nouns, reduction is a hypernym of tax shelter; that is, reduction is a word with a broader meaning than tax shelter:

tax shelter: a way of organizing business to reduce the taxes it must pay on current earnings
reduction: the act of decreasing or reducing something

Other hypernyms of tax shelter include decrease, diminution, step-down.

tax shelter (noun)	reduction (noun)
a way of organizing business to reduce the taxes it must pay on current earnings	the act of decreasing or reducing something
	the act of reducing complexity
	any process in which electrons are added to an atom or ion (as by removing oxygen or adding hydrogen); always occurs accompanied by oxidation of the reducing agent