to make something less or smaller in size, quantity, price, etc.; to become less or smaller in size, quantity, etc.

1[transitive] to make something less or smaller in size, quantity, price, etc. reduce something Reduce speed now (= on a sign). Giving up smoking reduces ...

​[usually passive] to force somebody/something into a particular state or condition, usually a worse one. a beautiful building reduced to rubble ...

to force someone or something into a particular state or condition, usually a worse one; a beautiful building reduced to rubble.

There are 80 meanings listed in OED's entry for the verb reduce, 34 of which are labelled obsolete. See 'Meaning & use' for definitions, usage, and quotation ...

to change something to a more general or more simple form. We can reduce the problem to two main issues.

The only known use of the noun reduce is in the mid 1500s. OED's only evidence for reduce is from 1549, in a letter by King Edward VI.

an act of making something less or smaller; the state of being made less or smaller. Extra Examples A small percentage reduction in the cost of materials would ...

​[usually passive] to force somebody/something into a particular state or condition, usually a worse one. a beautiful building reduced to rubble ...

an act of making something less or smaller; the state of being made less or smaller; a 33% reduction in the number of hospital beds available.