D defs.my
Entry 4 senses Webster, 1913

Reducer

/(-s?r)/ · Re·du·cer · IPA /ɹɪˈdusɚ/
01 n. One who, or that which, reduces.
  1. 1.
    One who, or that which, reduces.
  2. 2.
    A contrivance for reducing the dimensions of one part so as to fit it to another, as a reducing coupling, or a device for holding a drilling a chuck.(Mach.)
  3. 3.
    A reducing agent, either a developer or an agent for reducing density.(Photog.)
  4. 4.
    a reducing agent.(Chem.)