diminution
noun /ˌdɪmɪˈnjuːʃn/
  /ˌdɪmɪˈnuːʃn/
(formal)- [uncountable] diminution (of/in something) the act of reducing something or of being reduced
- the diminution of political power
 
 - [countable, usually singular] diminution (of/in something) a reduction; an amount reduced
- a diminution in population growth
 
 
Word OriginMiddle English: via Old French from Latin deminutio(n-), from the verb deminuere, from minuere ‘make small’.