Pronunciation: (ri-dOO'sur, -dyOO'-), [key]
1. a person or thing that reduces.
a. an oxidizing solution for lessening the density of an exposed negative.
b. a developing agent.
3. (in plumbing) a coupling decreasing in diameter at one end. Cf. increaser (def. 2).
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.