deduction vs diminution

deduction and diminution both are nouns.

Word	Noun	Adjective	Verb	Adverb
deduction	Yes	No	No	No
diminution	Yes	No	No	No

As nouns, diminution is a hypernym of deduction; that is, diminution is a word with a broader meaning than deduction:

Other hypernyms of deduction include decrease, reduction, step-down.

As nouns, diminution is a hypernym of deduction; that is, diminution is a word with a broader meaning than deduction:

Other hypernyms of deduction include decrease, reduction, step-down.

deduction (noun)	diminution (noun)
the act of subtracting (removing a part from the whole)	the act of decreasing or reducing something
the act of reducing the selling price of merchandise	the statement of a theme in notes of lesser duration (usually half the length of the original)
reasoning from the general to the particular (or from cause to effect)	change toward something smaller or lower
something that is inferred (deduced or entailed or implied)
an amount or percentage deducted
a reduction in the gross amount on which a tax is calculated; reduces taxes by the percentage fixed for the taxpayer's income bracket