'Retarder' definitions:

Definition of 'Retarder'

From: GCIDE
  • Retarder \Re*tard"er\, n.
  • 1. One who, or that which, retards. [1913 Webster]
  • 2. (Steam Boiler) Any of various devices, as a helix of flat metal strip, introduced into a boiler tube to increase the heating effect of the fire. [Webster 1913 Suppl.]
  • 3. (Photog.) A substance, as potassium bromide, added to a developer to retard its action. [Webster 1913 Suppl.]